Don't auto-switch keyboard if user uses in-app keyboard switcher

A user was confused why after selecting Gboard, the Key Mapper IME was immediately and automatically switched to. They wanted to manually select Gboard.

If the user is trying to switch keyboard inside the app, perhaps it should be clear about what is going on, or disable the auto switch feature, etc.

https://github.com/user-attachments/assets/466c90ba-5f42-4e58-a97e-ad791bf2a8a9