chore(ios): Add xcassets support

[ajanuar]

Description

This PR adds support for using .xcassets asset catalog icons across key navigation UI elements. Developers can now reference native asset names directly for both bottom-tab icons and header bar button items, removing the need to bundle standalone image files. By integrating with iOS/macOS asset catalogs, the update aligns icon handling with platform best practices, simplifies asset management, and enables automatic support for multi-resolution and variant images (such as dark mode).

Address discussion

Changes

Screenshots / GIFs

Here you can add screenshots / GIFs documenting your change.

You can add before / after section if you're changing some behavior.

Add logo to asset catalog

Bottom tabs

Header Bar Button Item

Menu

Submenu

Test code and steps to reproduce

Checklist

• Included code example that can be used to test this change
• Updated TS types
• Updated documentation:
  • https://github.com/software-mansion/react-native-screens/blob/main/guides/GUIDE_FOR_LIBRARY_AUTHORS.md
  • https://github.com/software-mansion/react-native-screens/blob/main/native-stack/README.md
  • https://github.com/software-mansion/react-native-screens/blob/main/src/types.tsx
  • https://github.com/software-mansion/react-native-screens/blob/main/src/native-stack/types.tsx
• Ensured that CI passes

[kkafar]

Hey! Thanks for the PR. We'll look into it after 4.19.0 release

[ajanuar]

Thank you @kkafar ! I'll add more tests