Disable test that is turning the tree red. (#9204)

This issue is being tracked at: https://github.com/dart-lang/sdk/issues/29230

dev/manual_tests/test/card_collection_test.dart

@@ -34,5 +34,5 @@ void main() {
     await tester.pump();
     await tester.tap(find.text('Vary font sizes'));
     await tester.pump();
-  });
+  }, skip: true); // https://github.com/dart-lang/sdk/issues/29230
 }