[BUG] - "Play Next" does not always work correctly

[gabehf]

Describe the bug

When shuffle is enabled, hitting "play next" on a track does not make that track play next. Also, if shuffle mode is toggled between hitting "play next" and the current track ending/hitting the skip button, the track does not play next.

Expected behavior

The track I hit "play next" on should be played next, regardless of shuffle state.

To Reproduce

1. Go to playlist or album
2. Start playing a song with shuffle on
3. Queue another track with "play next"
4. Wait until track finishes or skip, notice the queued track is not the one that plays

Environment

Version 4.6.0, Navidrome music server v0.59.0

Additional context

When I open the queue after hitting skip, I notice that the "play next" track is exactly one behind the currently playing track. Maybe just an off-by-one error in the play next logic, but I haven't looked at the code yet.