chore: add isJustified to segmented control in s2 example apps

[yihuiliao]

Closes

should fix the segmented control layout issues found in the example apps by applying isJustified since there's a custom width

✅ 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:

[rspbot]

Build successful! 🎉

• View the storybook
• View the storybook-19
• View the storybook-17
• View the storybook-16
• View the S2 storybook
• View the documentation

[yihuiliao]

feel free to make updates or merge while i'm on pto