[Android] Move code relating to `onTerminate()` in `FenixApplication.kt`

Summary

Summarize the bug encountered concisely.

onTerminate() in FenixApplication.kt "will never be called on a production Android device". We are overriding it to do more stuff and then calling it. I think we should instead move the "active" code to a different function and not use onTerminate() for this purpose.