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