Fix:-fixed dark mode appearance for the a11y and action sheet examples in … (#44795)

Summary:
Fixes the `a11y` and actionSheet examples in the RN tester iOS app, where in dark mode, some text were not taking the appropriate color

**Before**

<img width="401" alt="Screenshot 2024-06-05 at 5 28 28 PM" src="https://github.com/facebook/react-native/assets/72331432/a17f2713-66e8-45bc-9923-baa328f40839">

<img width="401" alt="Screenshot 2024-06-05 at 5 28 37 PM" src="https://github.com/facebook/react-native/assets/72331432/4ca765a1-ebff-41e5-97ba-84f4d274f0c3">

**After**

<img width="401" alt="Screenshot 2024-06-05 at 5 29 56 PM" src="https://github.com/facebook/react-native/assets/72331432/c4f82d2c-4602-4165-abef-5620cbe45446">

<img width="401" alt="Screenshot 2024-06-05 at 5 30 08 PM" src="https://github.com/facebook/react-native/assets/72331432/973558dd-854c-4eb8-91d6-a288ba7b0561">

## Changelog:

N/A

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[INTERNAL] [FIXED] - Fix RN tester Example appearance in dark mode for A11y and ActionSheet.

Pull Request resolved: https://github.com/facebook/react-native/pull/44795

Test Plan: Tested using the RN tester app.

Reviewed By: NickGerleman

Differential Revision: D58469005

Pulled By: huntie

fbshipit-source-id: 05f991f1c3efae7ccfc90535aaa62d6075aad18e