fix: tree focus management

[snowystinger]

Closes

Fixes an issue where focus would go to a tree collection if focus was on a key that became completely disabled

✅ 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:

1. Go to first storybook for s2 treeview
2. expand the projects item and click on the disabled row
3. change the disabled behavior from selection to all
4. keyboard navigate back to the treeview
5. it should focus on the first item, not on the collection as a whole

🧢 Your Project:

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[rspbot]

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• View the S2 docs
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[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the S2 docs
• View the React Aria docs

[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the S2 docs
• View the React Aria docs