Fixup for failing Beta CI (#2092)

Turns out, we shipped a new Flutter beta as well. 

Commenting out `experimental/varfont_shader_puzzle` from beta CI

Everything else is just cleanup.

## 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 updated/added relevant documentation (doc comments with `///`).
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-devrel
channel on [Discord].

<!-- Links -->
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[CLA]: https://cla.developers.google.com/
[Discord]: https://github.com/flutter/flutter/wiki/Chat
[Contributors Guide]:
https://github.com/flutter/samples/blob/main/CONTRIBUTING.md

web/samples_index/pubspec.yaml

@@ -4,7 +4,7 @@ homepage: https://github.com/flutter/samples/tree/main/web/samples_index
 version: 0.0.1
 
 environment:
-  sdk: ^3.1.0
+  sdk: ^3.2.0
 
 dependencies:
   json_annotation: ^4.8.1