[chore]: If empty for transformation then return empty dict

libs/community/langchain_community/callbacks/tracers/wandb.py

@@ -199,6 +199,8 @@ def transform_run(run: Dict[str, Any]) -> Dict[str, Any]:
         transformed_dict = transform_serialized(run)
 
         serialized = transformed_dict.pop("serialized")
+        if not serialized:
+            return {}
         for k, v in serialized.items():
             transformed_dict[k] = v