Update testing_app for upcoming release

[domesticmouse]

From failed CI run:

== Testing 'testing_app' on Flutter's beta channel ==
~/work/samples/samples/testing_app ~/work/samples/samples
Running "flutter pub get" in testing_app...                      1,992ms
Analyzing testing_app...                                        

   info • 'showSnackBar' is deprecated and shouldn't be used. Use ScaffoldMessenger.showSnackBar. This feature was deprecated after v1.23.0-14.0.pre. • lib/screens/favorites.dart:58:34 • deprecated_member_use
   info • 'showSnackBar' is deprecated and shouldn't be used. Use ScaffoldMessenger.showSnackBar. This feature was deprecated after v1.23.0-14.0.pre. • lib/screens/home.dart:70:34 • deprecated_member_use

[adarsh-technocrat]

Hello @domesticmouse 👋 it would be great if you allow me to land PR for all the issues related to the Update that you have created recently.

[redbrogdon]

I've brought the beta branch up to date so this can be landed there.

[adarsh-technocrat]

Hello @domesticmouse as related PR has been to merge to the beta branch we can close this issue :)

[domesticmouse]

Woohoo 🎉