Fix: tavily search error. (#5653)

### What problem does this PR solve?

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

agentic_reasoning/deep_research.py

 
                 if self.prompt_config.get("tavily_api_key"):
                     tav = Tavily(self.prompt_config["tavily_api_key"])
-                    tav_res = tav.retrieve_chunks(" ".join(search_query))
+                    tav_res = tav.retrieve_chunks(search_query)
                     kbinfos["chunks"].extend(tav_res["chunks"])
                     kbinfos["doc_aggs"].extend(tav_res["doc_aggs"])
                 if self.prompt_config.get("use_kg") and self._kg_retrieve:

rag/utils/tavily_conn.py

     def retrieve_chunks(self, question):
         chunks = []
         aggs = []
+        logging.info("[Tavily]Q: " + question)
         for r in self.search(question):
             id = get_uuid()
             chunks.append({
                 "count": 1,
                 "url": r["url"]
             })
-            logging.info("[Tavily]: "+r["content"][:128]+"...")
+            logging.info("[Tavily]R: "+r["content"][:128]+"...")
         return {"chunks": chunks, "doc_aggs": aggs}