Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/35028
**This Diff require a bump in the react-native-codegen (including this [commit](https://github.com/facebook/react-native/commit/7680bdeb4f96a8092393372a59c77a9d7b729cae)) to work**
This diff sets up iOS and Android to pass their platform to the codegen so that we can have platform-specific specs.
## Changelog
[General][Added] - Enable platform-specific Codegen Specs
Reviewed By: cortinico
Differential Revision: D40516395
fbshipit-source-id: 0624f0bfb93c90f78131a605a4847e780783bbaf