player: Fix missing current_track renaming

currentTrack attribute has been renamed to current_track. Some
references were missing.
2 jobs for wip/jfelder/fix-currenttrack in 5 minutes and 46 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Check
passed flake8 #17109

00:01:01

 
  Build
passed build #17110

00:04:45