community[patch]: add missing chunk parameter for _stream/_astream (#17807)

- Description: Add missing chunk parameter for _stream/_astream for some
chat models, make all chat models in a consistent behaviour.
- Issue: N/A
- Dependencies: N/A

libs/community/langchain_community/chat_models/baichuan.py

@@ -218,9 +218,10 @@ class ChatBaichuan(BaseChatModel):
                     m.get("delta"), default_chunk_class
                 )
                 default_chunk_class = chunk.__class__
-                yield ChatGenerationChunk(message=chunk)
+                cg_chunk = ChatGenerationChunk(message=chunk)
+                yield cg_chunk
                 if run_manager:
-                    run_manager.on_llm_new_token(chunk.content)
+                    run_manager.on_llm_new_token(chunk.content, chunk=cg_chunk)
 
     def _chat(self, messages: List[BaseMessage], **kwargs: Any) -> requests.Response:
         parameters = {**self._default_params, **kwargs}