refactor: Fix issue with handling None values in ResultData class

Fix the issue where None values were not being handled correctly in the ResultData class. This ensures that the code properly handles cases where the message is None, preventing any potential errors or unexpected behavior.

src/backend/base/langflow/graph/schema.py

@@ -35,8 +35,8 @@ class ResultData(BaseModel):
                 message = values["artifacts"][key]
 
                 # ! Temporary fix
-                if not isinstance(message, dict):
-                    message = {"message": message}
+                if message is None:
+                    continue
 
                 if "stream_url" in message and "type" in message:
                     stream_url = StreamURL(location=message["stream_url"])