refine multi-turn chat in agent (#2560)

### What problem does this PR solve?

#2484

### Type of change

- [x] Performance Improvement
- [ ] Other (please describe):

api/apps/llm_app.py

@@ -287,7 +287,7 @@ def delete_llm():
 @manager.route('/delete_factory', methods=['POST'])
 @login_required
 @validate_request("llm_factory")
-def delete_llm():
+def delete_factory():
     req = request.json
     TenantLLMService.filter_delete(
             [TenantLLM.tenant_id == current_user.id, TenantLLM.llm_factory == req["llm_factory"]])