Always clean up when coming out of the Pilot

src/textual/app.py

@@ -679,8 +679,9 @@ class App(Generic[ReturnType], DOMNode):
         app._set_active()
 
         # Context manager returns pilot object to manipulate the app
+        try:
             yield Pilot(app)
-
+        finally:
             # Shutdown the app cleanly
             await app._shutdown()
             await app_task