Refactor. (#4487)

### What problem does this PR solve?

### Type of change

- [x] Refactoring

api/apps/kb_app.py

@@ -116,8 +116,10 @@ def update():
         if not e:
             return get_data_error_result(
                 message="Database error (Knowledgebase rename)!")
+        kb = kb.to_dict()
+        kb.update(req)
 
-        return get_json_result(data=kb.to_json())
+        return get_json_result(data=kb)
     except Exception as e:
         return server_error_response(e)