Refactor (#4303)

### What problem does this PR solve?

### Type of change
- [x] Refactoring

api/apps/__init__.py

@@ -152,8 +152,8 @@ def load_user(web_request):
                 return user[0]
             else:
                 return None
-        except Exception:
-            logging.exception("load_user got exception")
+        except Exception as e:
+            logging.warning(f"load_user got exception {e}")
             return None
     else:
         return None

api/apps/conversation_app.py

@@ -65,10 +65,6 @@ def set_conversation():
             "message": [{"role": "assistant", "content": dia.prompt_config["prologue"]}]
         }
         ConversationService.save(**conv)
-        e, conv = ConversationService.get_by_id(conv["id"])
-        if not e:
-            return get_data_error_result(message="Fail to new a conversation!")
-        conv = conv.to_dict()
         return get_json_result(data=conv)
     except Exception as e:
         return server_error_response(e)