Websocket "getState" returns inconsistent information after last song in queue have played.

[Joni-Salminen]

After last song of queue is played, "position" will be reset to zero, rest of the information still points to the last song in the queue.

Steps to reproduce

1. add songs to queue
2. listen all songs(or select last from queue and rewind to very last seconds and wait till it ends naturally)
3. refresh the web gui with F5 (this simulates user opening the web gui again after the playback have ended)
4. "Now playing screen" shows the information about last song in the queue.
5. select Goto artist/album.
6. bug reproduces.

Tested on Rpi 4, Volumio 3.163 (Qobuz as music source)