Add final linting fix

Author: pgjones

src/quart/blueprints.py

@@ -315,7 +315,7 @@ def after_app_websocket(self, func: T_after_websocket) -> T_after_websocket:
             def after():
                 ...
         """
-        self.record_once(lambda state: state.app.after_websocket(func))  # type: ignore[attr-defined]
+        self.record_once(lambda state: state.app.after_websocket(func))  # type: ignore
         return func
 
     @setupmethod