fixup! fix(grpc): Return propagate proper metadata object instead of list in client interceptor

Author: fdellekart

sentry_sdk/integrations/grpc/aio/client.py

@@ -21,7 +21,8 @@ class ClientInterceptor:
     def _update_client_call_details_metadata_from_scope(
         client_call_details: ClientCallDetails,
     ) -> ClientCallDetails:
-        client_call_details.metadata = client_call_details.metadata or Metadata()
+        if client_call_details.metadata is None:
+            client_call_details = client_call_details._replace(metadata=Metadata())
         for key, value in Scope.get_current_scope().iter_trace_propagation_headers():
             client_call_details.metadata.add(key, value)
         return client_call_details