Enable SonarKit and Flipper in React-Core (#33499)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/33499

This DIFF turns on the `FB_SONARKIT_ENABLED` flag when installing Flipper ina RN app. The flag is enabled only in Debug config, given that Flipper is installed only in this configuration.

This PR also fixes this issue: https://github.com/facebook/react-native/issues/33497

This PR is required because release 0.67 has the Flag in the app, while release 0.68 moved it in the React-Core pod.
We can't enable the flag at the `React-Core.podspec` level because we should not make assumptions on whether users want flipper or not.

## Changelog
[iOS][Changed] - Enable SonarKit in React-Core when the configuration is `'Debug'`

Reviewed By: cortinico

Differential Revision: D35141506

fbshipit-source-id: 171b7fa8ea7727c633ef963408e86b332c32e9fa