fix(api): tolerate delete of nonexistent pip offset (#7027)

If you delete a pipette offset that doesn't exist, it really shouldn't
throw an exception and break a bunch of stuff.

Author: sfoster1

api/src/opentrons/calibration_storage/delete.py

@@ -135,8 +135,11 @@ def delete_pipette_offset_file(pipette: str, mount: Mount):
     offset_dir = config.get_opentrons_path('pipette_calibration_dir')
     offset_path = offset_dir / mount.name.lower() / f'{pipette}.json'
 
-    _remove_pipette_offset_from_index(pipette, mount)
-    offset_path.unlink()
+    try:
+        _remove_pipette_offset_from_index(pipette, mount)
+        offset_path.unlink()
+    except FileNotFoundError:
+        pass
 
 
 def clear_pipette_offset_calibrations():

robot-server/tests/integration/test_pipette_offset_access.tavern.yaml

@@ -142,4 +142,4 @@ stages:
         pipette_id: '321'
         mount: 'right'
     response:
-        status_code: 404
+        status_code: 200

robot-server/tests/service/pipette_offset/test_pipette_offset_management.py

@@ -43,15 +43,7 @@ def test_delete_pipette_offset_calibration(
     resp = api_client.delete(
         f'/calibration/pipette_offset?pipette_id={PIPETTE_ID}&'
         f'mount={WRONG_MOUNT}')
-    assert resp.status_code == 404
-    body = resp.json()
-    assert body == {
-        'errors': [{
-            'status': '404',
-            'title': 'Resource Not Found',
-            'detail': "Resource type 'PipetteOffsetCalibration' with id "
-                      "'123&right' was not found"
-        }]}
+    assert resp.status_code == 200
 
     resp = api_client.delete(
         f'/calibration/pipette_offset?pipette_id={PIPETTE_ID}&'