Ensure we prevent messages that were prevented when call_next was ori…

…ginally called (Textualize#4078)

src/textual/message_pump.py

@@ -592,7 +592,8 @@ async def _flush_next_callbacks(self) -> None:
         self._next_callbacks.clear()
         for callback in callbacks:
             try:
-                await self._dispatch_message(callback)
+                with self.prevent(*callback._prevent):
+                    await invoke(callback.callback)
             except Exception as error:
                 self.app._handle_exception(error)
                 break