3.38 / 3.10 (#2742)

This PR makes samples pass CI when 3.10 is released.

## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I have added sample code updates to the [changelog].
- [x] I updated/added relevant documentation (doc comments with `///`).

testing_app/test/favorites_test.dart

@@ -52,9 +52,7 @@ void main() {
       await tester.pumpAndSettle();
 
       // Get the total number of items available.
-      final totalItems = tester
-          .widgetList(find.byIcon(Icons.close))
-          .length;
+      final totalItems = tester.widgetList(find.byIcon(Icons.close)).length;
 
       // Remove one item.
       await tester.tap(find.byIcon(Icons.close).first);