fix(#1697): Provider: Better support for components rendered in ReactDOM.createPortal

[sdjustin]

Closes 1697

✅ Pull Request Checklist:

• [x] 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).
• [x] Filled out test instructions.
• [x] Updated documentation (if it already exists for this component).
• [x] Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

Use Provider -> isPortal (ReactDOM.createPortal) storybook example

Expected

Both checkboxes looks the same

🧢 Your Project:

Adobe