Fix missing required in Select (& HiddenSelect)

[Gregoor]

Hi,

I noticed the lack of a required prop on the Select comps, but I need it to block form submission. Hope it's alright to jump straight to PR without a prior issue, it seemed pretty clear to me that this will be needed.

✅ 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

[devongovett]

At the moment, none of our form components block native form submission. They use aria-required instead. So this would be a bigger change. I had started the work for native form validation support over in #4640.

[Gregoor]

Ah! I've been using react-arias <RadioGroup> in another place where disabled was working, so I guess my expectations got mixed up.

Would a PR adding it only to useSelect be more acceptable then?

[devongovett]

Yeah eventually, but it depends on the form validation stuff I linked to to avoid the browser's native validation UI. I am currently working on that, so I'll close this one out for now.