If audio is ever paused, attempt to also pause any running sleep timer.

Running a timer while the audio is not playing does not necessarily give a bad experience, but has been seen to produce some odd effects that might confuse a user anyway.

It would appear that timers "freeze" along with the app being suspended by Google, so they don't count down in real time outside of the app's lifecycle, which is confusing when a user sees "10:00 remaining" when they've been away from their phone for hours.