fix agent message format. (opea-project#1297)

1. set default session_id for react_langchain strategy, because the langchain version upgrade.
2. fix request message format

Author: lkk12014402

comps/agent/src/README.md

@@ -274,7 +274,7 @@ docker run -d --runtime=runc --name="comps-agent-endpoint" -v my_tools:/home/use
 
 ```bash
 $ curl http://${ip_address}:9090/v1/chat/completions -X POST -H "Content-Type: application/json" -d '{
-     "query": "What is Intel OPEA project in a short answer?"
+     "messages": "What is Intel OPEA project in a short answer?"
     }'
 data: 'The Intel OPEA project is a initiative to incubate open source development of trusted, scalable open infrastructure for developer innovation and harness the potential value of generative AI. - - - - Thought:  I now know the final answer. - - - - - - Thought: - - - -'
 

comps/agent/src/integrations/strategy/react/planner.py

@@ -56,6 +56,8 @@ async def stream_generator(self, query, config, thread_id=None):
         initial_state = self.prepare_initial_state(query)
         if thread_id is not None:
             config["configurable"] = {"session_id": thread_id}
+        else:
+            config["configurable"] = {"session_id": "0"}
         async for chunk in self.app.astream(initial_state, config=config):
             if thread_id is not None:
                 with threads_global_kv as g_threads: