Tweak Dev Menu appearance for iOS 26 (#53844)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53844

Small UI tweaks that help when scanning more visually spread out alert actions on iOS 26.

- Use bold (iOS 26 style) alert title.
- Differentiate "Cancel" actions with red system style.

Changelog: [Internal]

Reviewed By: christophpurrer

Differential Revision: D82731784

fbshipit-source-id: 0a0215fc75a4832e742e22328d5e21eee3808972