Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47636

We're cleaning up key spreads across WWW/Fbsource. Flow's `ban_spread_key_props` option allows us to fix existing spreads and prevent new ones from being added in code covered by Flow.

Here we fix spreads within xplat/js.

Also based on a unit test keeping config in sync, I've added the option to metro and RN OSS as well.

Changelog: [Internal]

Reviewed By: SamChou19815

Differential Revision: D64427942

fbshipit-source-id: db8f4aa428ce1994304b5d814b9d241d26e8d522