test: commit Files retirement transaction

tests/test_connector_credential_deletion.py

@@ -169,6 +169,10 @@ class ConnectorCredentialDeletionTests(unittest.TestCase):
             "govoplan_files.backend.storage.connector_credential_deletion.audit_event"
         ) as audit:
             plan.destroy_data_executor(self.session, "files")
+        # The retirement executor deliberately enlists secret scrubbing, audit
+        # writes, and DDL in the caller-owned transaction.  Commit that unit of
+        # work before inspecting through a separate Engine connection.
+        self.session.commit()
 
         self.assertEqual(2, audit.call_count)
         self.assertEqual(
@@ -193,6 +197,7 @@ class ConnectorCredentialDeletionTests(unittest.TestCase):
             "govoplan_files.backend.storage.connector_credential_deletion.audit_event"
         ) as audit:
             plan.destroy_data_executor(self.session, "files")
+        self.session.commit()
 
         audit.assert_called_once()
         details = audit.call_args.kwargs["details"]