Move E2E scripts to js (#48419)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/48419

This change moves the E2E scripts for iOS to a JS script.
This should make it much easier to modify the code in case we need to change it.

## Changelog
[Internal] - Move e2e script from bash to JS

Reviewed By: cortinico

Differential Revision: D67737950

fbshipit-source-id: d0b0411c8a4d688c10e460e70b11dbfc83aaa135