Add wasm-bindgen version check to CI

[jprochazk]

What

• Remove stored hashes and hash checks in JS package
• Add check for changes to wasm-bindgen version in CI

I believe our web viewer was broken since this PR:

• Update to latest wgpu and egui/eframe #7218

There were multiple people reviewing it (including myself with a "Web stuff LGTM" 🤦 ), and yet none of us remembered to check the output of wasm-bindgen. We clearly need something to remind us.

The new CI check added in this PR will compare the wasm-bindgen version to the one on main, and require the wasm-bindgen version update label if they differ. This is vastly better than committing and comparing hashes of the built files, because:

1. It's significantly faster on CI (doesn't require both release and debug Wasm builds)
2. It doesn't trigger when the hash of the output changes for reasons other than the version of wasm-bindgen changing

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!
• If have noted any breaking changes to the log API in CHANGELOG.md and the migration guide

• PR Build Summary
• Recent benchmark results
• Wasm size tracking

To run all checks from main, comment on the PR with @rerun-bot full-check.