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/_tool/pubspec.yaml

@@ -2,7 +2,7 @@ name: tool
 publish_to: none
 
 environment:
-  sdk: ^3.1.0
+  sdk: ^3.2.0
 
 dependencies:
   markdown: ^7.0.0

web/_tool/verify_packages.dart

@@ -27,7 +27,7 @@ void main() async {
     ]));
     results.add(await run(
       dir,
-      'flutter',
+      'dart',
       ['analyze', '--fatal-infos', '--fatal-warnings', '.'],
     ));
     _printStatus(results);