Fix shuffle by grouping

[toy]

Check-list

• [ ] There is a linked issue discussing the motivations for this feature or bugfix
• [ ] Unit tests have been added where possible
• [ ] I've added / updated documentation for any user-facing features.
• [x] Performance seems to be comparable or better than current main

What this change is adding / fixing

This PR is caused by unexpected behaviour when going back'n'forth between groupings. Fox example if there are albums A, B and C (and grouping is done by album), if complete album A plays out and shuffle selects album B, and I press previous and last track of A starts playing, but next track afterwards will be randomly B or C, while I would still expect it to be B.