Fix IndexOutOfBoundsException on service start

[marverenic]

Completes #166859204.

This fixes an issue where the player service would crash when restoring its state on launch if there are songs that could not be found in the saved state.

Testing Steps

• Begin playing music
• Skip to the last track in the queue
• Close Jockey
• Delete the file for the previously playing song from the device entirely
• Restart Jockey

Expected Behavior:

• Jockey should restore as much of the queue as possible

Actual Behavior:

• The player service crashes on startup

Stacktrace:

Caused by java.lang.IllegalArgumentException: index must be smaller than the queue size (1)
       at com.marverenic.music.player.QueuedExoPlayer.setQueue(QueuedExoPlayer.java:235)
       at com.marverenic.music.player.MusicPlayer.setBackingQueue(MusicPlayer.java:922)
       at com.marverenic.music.player.MusicPlayer.restorePlayerState(MusicPlayer.java:1300)
       at com.marverenic.music.player.extensions.persistence.PersistenceExtension.onCreateMusicPlayer(PersistenceExtension.java:31)
       at com.marverenic.music.player.MusicPlayer.(MusicPlayer.java:258)
       at com.marverenic.music.player.PlayerService.onCreate(PlayerService.java:110)
       at android.app.ActivityThread.handleCreateService(ActivityThread.java:3750)
       at android.app.ActivityThread.access$1400(ActivityThread.java:237)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1801)
       at android.os.Handler.dispatchMessage(Handler.java:106)
       at android.os.Looper.loop(Looper.java:214)
       at android.app.ActivityThread.main(ActivityThread.java:7045)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)