[RFC] Update Community CLI plugin dependencies (0.87 changes)

[huntie]

Summary

Note

RFC: I need to ready RN and Community CLI PRs paired with this proposal. This template PR represents the new end state for users.

Depends on:

• Move Community CLI discovery config into plugin package react/react-native#57352
• Remove Community CLI platform config (upstreamed) react/react-native#57353
• breaking: Bundle iOS and Android as core platforms cli#2817

Motivation: @react-native/community-cli-plugin is currently an unconditional dependency of react-native, even for Expo users.

• Additionally, we maintain a CLI-coupled react-native.config.js file in the react-native package, which we can largely remove after these changes.
• Pulling this plugin in implicitly is unnecessary when CLI has its own plugin discovery mechanism.

This change

• Depend on @react-native/community-cli-plugin explicitly in the template, meaning we can drop the reference from core in React Native 0.87.
• To make this more palatable for users, also bundle another proposed change in 0.87 — make cli-platform-android, cli-platform-ios builtin dependencies of the CLI.
  • I note that CLI was historically separated out into granular plugins. However, some plugins (e.g. cli-doctor) remain built in. Separating the core platforms provides little value when RN itself bundles both — match this baseline.
  • Prior art: Expo CLI doesn't bother separating these — the dev install impact on projects is negligible. No artifacts leak into the project.

Changelog:
[General][Breaking] - Update required Community CLI plugins

• @react-native-community/cli-platform-android/cli-platform-ios are no longer required
• @react-native/community-cli-plugin is now mandatory

Test Plan

TODO

[thymikee]

I think I'd be good with these changes. Curious what OOT platforms say: @Saadnajmi @acoates-ms