feat: Support Ref Cleanup

[chirokas]

Closes

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

🧢 Your Project:

[snowystinger]

Thanks for the interest, it appears this is a React 19 only feature https://react.dev/blog/2024/12/05/react-19#cleanup-functions-for-refs

I noticed that all the tests, React 16, 17 and 18, pass. How much of the work here makes it work with previous versions? I still get a console warning if I try to use it, so I don't think it's a use case we should support. We can turn off the test for the other versions of React.

[chirokas]

I still get a console warning if I try to use it

// React 16, 17 and 18

<input ref={mergeRefs(onRefChangeWithCleanup)} />
// Warning: Unexpected return value from a callback ref
// https://github.com/facebook/react/pull/22313

We don't handle ref cleanups internally, so this still happens in React < 19 when a user's ref callback returns a value.

However, it works well

<input ref={useObjectRef(mergeRefs(onRefChangeWithCleanup))} />

[snowystinger]

Initially looks good, I've added some preliminary mergeRef tests in case we think of others edge cases we should try