gapic-generator-python Assertion error in generated unit tests for `x-goog-request-params` header

Affected APIs:

//google/cloud/run/v2/run_py_gapic_test

Failure example:

google/cloud/run/v2/run_py_gapic_srcjar.py/tests/unit/gapic/run_v2/test_revisions.py:1014: AssertionError
___________________________ test_list_services_pager ___________________________

transport_name = 'grpc'

    def test_list_services_pager(transport_name: str = "grpc"):
        client = ServicesClient(
            credentials=ga_credentials.AnonymousCredentials,
            transport=transport_name,
        )
    
        # Mock the actual call within the gRPC stub, and fake the request.
        with mock.patch.object(
                type(client.transport.list_services),
                '__call__') as call:
            # Set the response to a series of pages.
            call.side_effect = (
                service.ListServicesResponse(
                    services=[
                        service.Service(),
                        service.Service(),
                        service.Service(),
                    ],
                    next_page_token='abc',
                ),
                service.ListServicesResponse(
                    services=[],
                    next_page_token='def',
                ),
                service.ListServicesResponse(
                    services=[
                        service.Service(),
                    ],
                    next_page_token='ghi',
                ),
                service.ListServicesResponse(
                    services=[
                        service.Service(),
                        service.Service(),
                    ],
                ),
                RuntimeError,
            )
    
            metadata = ()
            metadata = tuple(metadata) + (
                gapic_v1.routing_header.to_grpc_metadata((
                    ('parent', ''),
                )),
            )
            pager = client.list_services(request={})
    
>           assert pager._metadata == metadata
E           AssertionError: assert () == (('x-goog-req..., 'parent='),)
E             Right contains one more item: ('x-goog-request-params', 'parent=')
E             Use -v to get more diff

google/cloud/run/v2/run_py_gapic_srcjar.py/tests/unit/gapic/run_v2/test_services.py:1246: AssertionError
=========================== short test summary info ============================
FAILED google/cloud/run/v2/run_py_gapic_srcjar.py/tests/unit/gapic/run_v2/test_revisions.py::test_list_revisions_pager
FAILED google/cloud/run/v2/run_py_gapic_srcjar.py/tests/unit/gapic/run_v2/test_services.py::test_list_services_pager
2 failed, 276 passed, 81 warnings in 1.69s