make imports more robust to partial rollout

Summary:
A large number of `.thrift` files pick-up dependencies on `fb303.thrift` or some other base class via `service MyService extends fb303.FacebookService {...}`. That makes it hard to do a partial in-place migration based on all these build graph edges to these core service `.thrift` files.

However, this dependency is never used in types, i.e., as a thrift field, so it's not actually a blocker for in-place migration.

To avoid import error from un-migrated thrift file, switch the dependency imports to `.types`, which contains aliases to the `inplace.py` types (or regular cython types if un-migrated).

Reviewed By: prakashgayasen

Differential Revision: D77401568

fbshipit-source-id: 78a400441137506e442f38a02a619219682d4c96

Author: ahilger

third-party/thrift/src/thrift/compiler/generate/templates/py3/types_inplace_FBTHRIFT_ONLY_DO_NOT_USE.py.mustache

@@ -48,7 +48,7 @@ import {{#program:py3Namespaces}}{{value}}.{{/program:py3Namespaces}}{{program:n
 
 {{#program:includeNamespaces}}
 {{#hasTypes?}}
-import {{#includeNamespace}}{{value}}.{{/includeNamespace}}types_inplace_FBTHRIFT_ONLY_DO_NOT_USE as _{{#includeNamespace}}{{value}}_{{/includeNamespace}}types
+import {{#includeNamespace}}{{value}}.{{/includeNamespace}}types as _{{#includeNamespace}}{{value}}_{{/includeNamespace}}types
 {{#program:hasConstants}}
 import {{#includeNamespace}}{{value}}.{{/includeNamespace}}types
 {{/program:hasConstants}}

third-party/thrift/src/thrift/compiler/test/fixtures/interactions/out/py3_inplace/gen-py3/test/fixtures/interactions/module/types_inplace_FBTHRIFT_ONLY_DO_NOT_USE.py

@@ -27,7 +27,7 @@
 import test.fixtures.interactions.module.thrift_enums as _fbthrift_python_enums
 
 
-import test.fixtures.another_interactions.shared.types_inplace_FBTHRIFT_ONLY_DO_NOT_USE as _test_fixtures_another_interactions_shared_types
+import test.fixtures.another_interactions.shared.types as _test_fixtures_another_interactions_shared_types
 
 def get_types_reflection():
     return importlib.import_module(

third-party/thrift/src/thrift/compiler/test/fixtures/types/out/py3_inplace/gen-py3/apache/thrift/fixtures/types/module/types_inplace_FBTHRIFT_ONLY_DO_NOT_USE.py

@@ -27,7 +27,7 @@
 import apache.thrift.fixtures.types.module.thrift_enums as _fbthrift_python_enums
 
 
-import apache.thrift.fixtures.types.included.types_inplace_FBTHRIFT_ONLY_DO_NOT_USE as _apache_thrift_fixtures_types_included_types
+import apache.thrift.fixtures.types.included.types as _apache_thrift_fixtures_types_included_types
 
 def get_types_reflection():
     return importlib.import_module(