chore: add ActionList primitives exports

[francinelucca]

Exporting some primitives for https://github.com/github/primer/issues/6456

This pull request refactors and enhances the FilteredActionList and related components in the Primer React library. The main focus is on improving the modularity and extensibility of FilteredActionList by extracting the input field logic into its own component, updating exports for better accessibility, and adding new utility exports. There are also minor improvements to ActionList and SelectPanel, as well as updates to test snapshots and type exports.

New

• Extracted the input logic from FilteredActionList into a new FilteredActionListInput component for better separation of concerns and reusability. The main component now uses this new input component.
• Exposed the SelectPanelMessage component and added it as a property of SelectPanel for easier access.
• Added or updated exports for additional types and utilities, including ActionListGroupHeadingProps, ActionListTrailingActionProps, and FocusKeys, to make them available for consumers of the package.
• Updated the FilteredActionList export to include the new Input and BodyLoader subcomponents, and re-exported relevant types and loading constants for improved modularity.

Changed

• Updated test snapshots to reflect the new and updated exports, ensuring test coverage stays in sync with the public API.

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

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-ui (Learn more about how to run integration tests)

[changeset-bot]

🦋 Changeset detected

Latest commit: 30fe2c4

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	Minor

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[github-actions]

⚠️ Action required

👋 Hi, this pull request contains changes to the source code that github/github-ui depends on. If you are GitHub staff, test these changes with github/github-ui using the integration workflow. Check the integration testing docs for step-by-step instructions. Or, apply the integration-tests: skipped manually label to skip these checks.

To publish a canary release for integration testing, apply the Canary Release label to this PR.

[Copilot]

@copilot what is causing the react 19 tests to fail?

The React 19 failures are all in src/TreeView/TreeView.test.tsx — the rendered body is empty (<div />) when those tests run, so element queries like getByRole("treeitem") and getByRole("button") can't find anything. This is unrelated to our PR changes: the exact same TreeView failures appear on the main branch at the same point in time (e.g. CI run 25078575410 on main fails identically). It looks like a pre-existing flaky test issue in the TreeView test suite under the React 19 environment, not something introduced by the ActionList/SelectPanel/FilteredActionList exports work here.

[primer-integration]

👋 Hi from github/github-ui! Your integration PR is ready: https://github.com/github/github-ui/pull/19663

[primer-integration]

Integration test results from github/github-ui:

  CI Passed
  VRT Passed
  Projects Passed

All checks passed!