Add conditional Android/iOS job runs in test-all workflow (#55449)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/55449

Further workflow optimisation after D92417918. Aims to improve speed of CI signals and reduce costs by excluding Android and iOS specific jobs when a PR contains changes exclusively within native code to one platform.

Changelog: [Internal]

Reviewed By: NickGerleman

Differential Revision: D92512983

fbshipit-source-id: feb67ce140014352219ae2b5720fc819ec5e1c11