add missing React-RCTSettings (#51523)

Summary:
Added missing module React-RCTSettings to the Swift package.

This was found when testing intergrating with a bare bones React Native project.

## Changelog:

[IOS] [FIXED] - add missing React-RCTSettings to Swift package

Pull Request resolved: https://github.com/facebook/react-native/pull/51523

Test Plan: Run against a bare bones React Native project (not available in repo yet)

Reviewed By: rshest

Differential Revision: D75204445

Pulled By: cipolleschi

fbshipit-source-id: d9fcb27cc532846eece591152462ff9c88f82302