Instability testing with Xcode 15

Using EarlGrey with Xcode 15 in our project, we are seeing several issues
- We are get a lot of application waiting to idle errors that we aren't seeing when running EarlGrey on Xcode 14. We have to turn off synchronization to test the app
- Some tapping motions aren't performing the tap correctly, particularly on UITabBar
- Matchers with grey_interactable() are failing even though the selected element is there and interactable

Wanted to know if others are also dealing with these or any other issues as I can either modify the way we're writing tests or start to look at improvements to EG2'S Xcode 15 compatibility

(We are running on the latest commit of EarlGrey)

Start by reproducing the application-idle, UITabBar tapping, and grey_interactable() failures with EarlGrey on Xcode 15, then compare the same tests on Xcode 14. Done means identifying which failures are Xcode 15 compatibility issues and documenting or addressing the affected behavior.

Written by the indexing model from the issue text.