SelectPanel Select all feature

[llastflowers]

Closes https://github.com/github/primer/issues/5348

Changelog

New

• Added Select all section with checkbox in SelectPanel
  • Select all checkbox selects all filtered items
  • Manually selecting all items automatically checks Select all box
  • Select all label changes to Deselect all when all items are selected
  • Deselect all checkbox deselects all filtered items
  • Manually checking some items but not all results in indeterminate checkbox state
  • Clicking Select all checkbox in indeterminate state selects all remaining filtered items
• Added With Select All story for SelectPanel
• Added new story to e2e
• Added unit tests

Changed

N/A

Removed

N/A

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why

Testing & Reviewing

Preview Link

This feature is designed to visually match the ModernActionList version of SelectPanel, so please toggle that feature flag on in Storybook when testing. (It still works without the FF, but just looks a bit goofy with the old SelectPanel design).

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[github-actions]

👋 Hi, this pull request contains changes to the source code that github/github depends on. If you are GitHub staff, we recommend testing these changes with github/github using the integration workflow. Thanks!

[changeset-bot]

🦋 Changeset detected

Latest commit: c404a19

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/react	Patch

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[github-actions]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	92.26 KB (+0.32% 🔺)
packages/react/dist/browser.umd.js	92.35 KB (+0.15% 🔺)

[primer-integration]

👋 Hi from github/github! Your integration PR is ready: https://github.com/github/github/pull/391216

[primer-integration]

🟢 golden-jobs completed with status success.

[langermank]

Left a non blocking suggestion but could easily be a followup!

[github-actions]

👋 Hi, there are new commits since the last successful integration test. We recommend running the integration workflow once more, unless you are sure the new changes do not affect github/github. Thanks!