Refactor Hermes workspace (#45071)

Summary:
This change is the first step in refactoring GHA so that they can be reused more easily across jobs.
Its goal is also to be more reliable w.r.t. caches.

That this change do:
* moves `prepare_hermes_workspace` to a composite action
	* saves the `prepare_hermes_workspace` caches only on main
	* uploads the destination folder as an artifact so that we can use it later in the run
* makes the `test-all`, `nightly` and `publish-release` workflow use the new composite action
* updates the `setup-hermes-workspace` to download and use the artifact uploaded by `prepare_hermes_workspace`

## Changelog:
[Internal] - Factor out the prepare_hermes_workspace action

Pull Request resolved: https://github.com/facebook/react-native/pull/45071

Test Plan: GHA in CI

Reviewed By: cortinico

Differential Revision: D58808087

Pulled By: cipolleschi

fbshipit-source-id: 42c46bcf75fc73b2edfda9be62b5d0fe8a919a5d