remove alter log (#2140)

### What problem does this PR solve?


### Type of change
- [x] Refactoring

api/apps/api_app.py

@@ -210,6 +210,7 @@ def completion():
         else:
             conv.reference[-1] = ans["reference"]
         conv.message[-1] = {"role": "assistant", "content": ans["answer"], "id": message_id}
+        ans["id"] = message_id
 
     def rename_field(ans):
         reference = ans['reference']