Implement blurEffect for new arch

[janicduplessis]

Description

Implements blurEffect header config for new arch.

Changes

I kept this super simple and used string for codegen so we can simply reuse the RCTConvert implementation.

Test code and steps to reproduce

Tested that header blur now works in an app with new arch enabled.

Checklist

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