ActionMenu: Don't allow items to be unchecked in single-select mode

[camertron]

What are you trying to accomplish?

We received a bug report in Slack today mentioning that items in an ActionMenu in single-select mode can be unchecked. The React component does not allow items to be unchecked, which I believe is how the PVC component should work as well.

Integration

I don't believe this change requires any updates to production code.

Risk Assessment

• Low risk the change is small, highly observable, and easily rolled back.
• Medium risk changes that are isolated, reduced in scope or could impact few users. The change will not impact library availability.
• High risk changes are those that could impact customers and SLOs, low or no test coverage, low observability, or slow to rollback.

Accessibility

• No new axe scan violation - This change does not introduce any new axe scan violations.

Merge checklist

• Added/updated tests
• Added/updated previews (Lookbook)
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge

Take a look at the What we look for in reviews section of the contributing guidelines for more information on how we review PRs.

[changeset-bot]

🦋 Changeset detected

Latest commit: f8f39b7

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

This PR includes changesets to release 1 package

Name	Type
@primer/view-components	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR