Remove unused rn-tester e2e tests (#45032)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/45032

Those tests haven't been running since ~1 year now.
I know it's not ideal but I'd rather remove them instead of keeping them around not executing.
We can still revert them back from the history once we decide to revive the E2E testing effort.

Changelog:
[Internal] [Changed] - Remove unused rn-tester e2e tests

Reviewed By: cipolleschi

Differential Revision: D58729123

fbshipit-source-id: f0f47e3c2e087141fdff506b7c5c9b460263721b