Move Community CLI discovery config into plugin package (1/2)

[huntie]

Summary:

Replaces #57352.

Self-register commands from the community-cli-plugin package via react-native.config.js — meaning we can remove the redirect within packages/react-native/react-native.config.js.

Progress towards removing community-cli-plugin as a direct dep of react-native, and paired with react-native-community/template#235.

RNTester and HelloWorld list @react-native/community-cli-plugin in devDependencies, as the template now does (react-native-community/template#235).

Changelog:
[General][Breaking] - @react-native/community-cli-plugin will no longer be auto-detected from react-native. It must now be specified in devDependencies.

Test Plan:

Compared react-native config output with @react-native-community/cli 20.2.0.

RNTester

• ✅ Commands, platforms, and project config are unchanged from main
• ✅ Removing the new @react-native/community-cli-plugin devDependency drops bundle, start, spm, and codegen, so they are registered by plugin discovery

Template-shaped app (plugin in devDependencies, no project react-native.config.js)

• ✅ bundle, start, spm, and codegen are registered

[meta-codesync]

@Abbondanzo has imported this pull request. If you are a Meta employee, you can view this in D121634885.

[meta-codesync]

@Abbondanzo merged this pull request in b26baae.