ref(cells): Remove no-longer-needed shims for getsentry

[lynnagara]

these were part of the region_name -> cell_name migration and are no longer needed

switch all remaining callers of region_name to cell_name

depends on https://github.com/getsentry/getsentry/pull/19500 and https://github.com/getsentry/getsentry/pull/19503

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[github-actions]

Backend Test Failures

Failures on b1ac433 in this run:

tests/sentry/middleware/integrations/parsers/test_plugin.py::PluginRequestParserTest::test_routing_webhooks_with_region — log

.venv/lib/python3.13/site-packages/django/db/models/options.py:683: in get_field
    return self.fields_map[field_name]
E   KeyError: 'region_name'

During handling of the above exception, another exception occurred:
tests/sentry/middleware/integrations/parsers/test_plugin.py:47: in test_routing_webhooks_with_region
    OrganizationMapping.objects.get(organization_id=self.organization.id).update(
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
src/sentry/db/models/query.py:92: in update
    instance.__class__.objects.using(using)
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
src/sentry/db/models/manager/base_query_set.py:92: in update
    return super().update(**kwargs)
.venv/lib/python3.13/site-packages/django/db/models/query.py:1237: in update
    query.add_update_values(kwargs)
.venv/lib/python3.13/site-packages/django/db/models/sql/subqueries.py:88: in add_update_values
    field = self.get_meta().get_field(name)
.venv/lib/python3.13/site-packages/django/db/models/options.py:685: in get_field
    raise FieldDoesNotExist(
E   django.core.exceptions.FieldDoesNotExist: OrganizationMapping has no field named 'region_name'

tests/sentry/synapse/endpoints/test_org_cell_mappings.py::OrgCellMappingsTest::test_get_results_no_next — log

tests/sentry/synapse/endpoints/test_org_cell_mappings.py:71: in test_get_results_no_next
    assert res.status_code == 200
E   assert 500 == 200
E    +  where 500 = <Response status_code=500, "application/json">.status_code

tests/sentry/synapse/endpoints/test_org_cell_mappings.py::OrgCellMappingsTest::test_get_next_page — log

tests/sentry/synapse/endpoints/test_org_cell_mappings.py:92: in test_get_next_page
    assert res.status_code == 200
E   assert 500 == 200
E    +  where 500 = <Response status_code=500, "application/json">.status_code

tests/sentry/middleware/integrations/parsers/test_bitbucket_server.py::BitbucketServerRequestParserTest::test_routing_webhook — log

.venv/lib/python3.13/site-packages/django/db/models/options.py:683: in get_field
    return self.fields_map[field_name]
E   KeyError: 'region_name'

During handling of the above exception, another exception occurred:
tests/sentry/middleware/integrations/parsers/test_bitbucket_server.py:37: in test_routing_webhook
    OrganizationMapping.objects.get(organization_id=self.organization.id).update(
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
src/sentry/db/models/query.py:92: in update
    instance.__class__.objects.using(using)
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
src/sentry/db/models/manager/base_query_set.py:92: in update
    return super().update(**kwargs)
.venv/lib/python3.13/site-packages/django/db/models/query.py:1237: in update
    query.add_update_values(kwargs)
.venv/lib/python3.13/site-packages/django/db/models/sql/subqueries.py:88: in add_update_values
    field = self.get_meta().get_field(name)
.venv/lib/python3.13/site-packages/django/db/models/options.py:685: in get_field
    raise FieldDoesNotExist(
E   django.core.exceptions.FieldDoesNotExist: OrganizationMapping has no field named 'region_name'

tests/sentry/synapse/endpoints/test_org_cell_mappings.py::OrgCellMappingsTest::test_get_locale_filter — log

tests/sentry/synapse/endpoints/test_org_cell_mappings.py:149: in test_get_locale_filter
    assert res.status_code == 200
E   assert 500 == 200
E    +  where 500 = <Response status_code=500, "application/json">.status_code

tests/sentry/api/endpoints/test_accept_organization_invite.py::AcceptInviteTest::test_multi_region_organizationmember_id — log

tests/sentry/api/endpoints/test_accept_organization_invite.py:159: in test_multi_region_organizationmember_id
    self.create_organization_mapping(
src/sentry/testutils/fixtures.py:666: in create_organization_mapping
    return Factories.create_org_mapping(*args, **kwargs)
/opt/hostedtoolcache/Python/3.13.1/x64/lib/python3.13/contextlib.py:85: in inner
    return func(*args, **kwds)
src/sentry/testutils/factories.py:434: in create_org_mapping
    return OrganizationMapping.objects.create(**kwds)
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
.venv/lib/python3.13/site-packages/django/db/models/manager.py:87: in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
.venv/lib/python3.13/site-packages/django/db/models/query.py:663: in create
    obj = self.model(**kwargs)
.venv/lib/python3.13/site-packages/django/db/models/base.py:569: in __init__
    raise TypeError(
E   TypeError: OrganizationMapping() got unexpected keyword arguments: 'region_name'

tests/sentry/hybridcloud/test_rpc.py::RpcServiceTest::test_remote_service — log

tests/sentry/hybridcloud/test_rpc.py:68: in test_remote_service
    service.add_organization_member(
src/sentry/hybridcloud/rpc/service.py:346: in remote_method
    result = signature.resolve_to_region(kwargs)
src/sentry/hybridcloud/rpc/service.py:119: in resolve_to_region
    region = self._region_resolution.resolve(arguments)
src/sentry/hybridcloud/rpc/resolvers.py:66: in resolve
    return self._get_from_mapping(organization_id=organization_id)
src/sentry/hybridcloud/rpc/resolvers.py:35: in _get_from_mapping
    return get_cell_by_name(mapping.cell_name)
src/sentry/types/region.py:331: in get_cell_by_name
    raise RegionResolutionError(
E   sentry.types.region.RegionResolutionError: No cell with name: 'testregion467840' (expected one of ['north_america', 'europe'] or a single-tenant name)

tests/sentry/middleware/integrations/parsers/test_bitbucket.py::BitbucketRequestParserTest::test_routing_webhook_no_regions — log

.venv/lib/python3.13/site-packages/django/db/models/options.py:683: in get_field
    return self.fields_map[field_name]
E   KeyError: 'region_name'

During handling of the above exception, another exception occurred:
tests/sentry/middleware/integrations/parsers/test_bitbucket.py:69: in test_routing_webhook_no_regions
    OrganizationMapping.objects.get(organization_id=self.organization.id).update(
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
src/sentry/db/models/query.py:92: in update
    instance.__class__.objects.using(using)
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
src/sentry/db/models/manager/base_query_set.py:92: in update
    return super().update(**kwargs)
.venv/lib/python3.13/site-packages/django/db/models/query.py:1237: in update
    query.add_update_values(kwargs)
.venv/lib/python3.13/site-packages/django/db/models/sql/subqueries.py:88: in add_update_values
    field = self.get_meta().get_field(name)
.venv/lib/python3.13/site-packages/django/db/models/options.py:685: in get_field
    raise FieldDoesNotExist(
E   django.core.exceptions.FieldDoesNotExist: OrganizationMapping has no field named 'region_name'

tests/sentry/middleware/integrations/parsers/test_plugin.py::PluginRequestParserTest::test_routing_webhooks_no_region — log

.venv/lib/python3.13/site-packages/django/db/models/options.py:683: in get_field
    return self.fields_map[field_name]
E   KeyError: 'region_name'

During handling of the above exception, another exception occurred:
tests/sentry/middleware/integrations/parsers/test_plugin.py:28: in test_routing_webhooks_no_region
    OrganizationMapping.objects.get(organization_id=self.organization.id).update(
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
src/sentry/db/models/query.py:92: in update
    instance.__class__.objects.using(using)
src/sentry/silo/base.py:158: in override
    return original_method(*args, **kwargs)
src/sentry/db/models/manager/base_query_set.py:92: in update
    return super().update(**kwargs)
.venv/lib/python3.13/site-packages/django/db/models/query.py:1237: in update
    query.add_update_values(kwargs)
.venv/lib/python3.13/site-packages/django/db/models/sql/subqueries.py:88: in add_update_values
    field = self.get_meta().get_field(name)
.venv/lib/python3.13/site-packages/django/db/models/options.py:685: in get_field
    raise FieldDoesNotExist(
E   django.core.exceptions.FieldDoesNotExist: OrganizationMapping has no field named 'region_name'

tests/sentry/synapse/endpoints/test_org_cell_mappings.py::OrgCellMappingsTest::test_get_multiple_pages_multiple_locales — log

tests/sentry/synapse/endpoints/test_org_cell_mappings.py:113: in test_get_multiple_pages_multiple_locales
    assert res.status_code == 200
E   assert 500 == 200
E    +  where 500 = <Response status_code=500, "application/json">.status_code

[lynnagara]

needs https://github.com/getsentry/getsentry/pull/19503 first for the getsentry tests to pass