chore: adding width picker to tab collapse story for mobile testing

[ktabors]

From testing. We couldn't test tab collapse on mobile.

✅ 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:

test "Tabs" -> "Dynamic" on a mobile device

🧢 Your Project:

RSP

[rspbot]

Build successful! 🎉

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• View the S2 storybook
• View the documentation

[snowystinger]

I decided to take a different approach that doesn't involve a picker in fix: Tabs from testing
I think we can close this one.

of note, it's still horrible on iOS18 because of the iOS18 bug, i'd forgotten how bad it was