Merge branch 'csm_interceptor' into csm_1_data_model

Author: daniel-sanche

google/cloud/bigtable/data/_sync_autogen/metrics_interceptor.py

@@ -124,4 +124,4 @@ def _streaming_generator_wrapper(operation, call):
             if call is not None:
                 metadata = _get_metadata(encountered_exc or call)
                 if metadata is not None:
-                    operation.add_response_metadata(metadata)
+                    operation.add_response_metadata(metadata)