Queue lost when player service loses foreground.

When FFA loses focus while playback is paused, Android kills it off after about a minute. When playback is restarted, or FFA is subsequently launched, the queue is empty.

Pressing play without relaunch leaves the impression that the player simply will not start. The logs report a fatal exception with the rather obscure error:

android.app.RemoteServiceException$ForegroundServiceDidNotStartInTimeException: Context.startForegroundService() did not then call Service.startForeground(): ServiceRecord{a5f144a u0 audio.funkwhale.ffa.dev/audio.funkwhale.ffa.playback.PlayerService}