Create TurboModule for test helpers (#48283)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/48283

Migrate from custom JSI integration to use TurboModule base-class.

This doesn't use codegen right now for ease of migration, and to avoid needing to setup a js_library buck definition for react-native-fantom. We should also figure out what the right abstraction/division of responsibilities is going forward for TesterAppDelegate and FantomModule.

Changelog: [Internal]

Reviewed By: rubennorte

Differential Revision: D67111850

fbshipit-source-id: e1623d80f1f25ec123315b3620930dd17dd8a8a7