Do not setup-node twice in test_js (#52737)

Summary:
I've noticed that test_js (20) and test_js (24) are actually running on Node 22.
That's because the `yarn-install` action is invoking setup-node again with the default value (22).

This changes it. Also I'm cleaning up the workflows so that every `yarn-install` invocation is happening just after the `setup-node` invocation.

## Changelog:

[INTERNAL] -

Pull Request resolved: https://github.com/facebook/react-native/pull/52737

Test Plan: CI which will most likely be red for test_js (20) so will need a follow-up

Reviewed By: cipolleschi

Differential Revision: D78664671

Pulled By: cortinico

fbshipit-source-id: c73390930d1511d1bf0f2d4ea92e83f50b10247f