Instrumental (5) and Vocals (6) overlapped with Title|MP3 and
Artist|MP3 in the [Flags] enum. A song file with #INSTRUMENTAL or
#VOCALS therefore passed the mandatory-tag checks even when #TITLE,
#ARTIST or #MP3 were missing, leaving Audio empty.
Give each flag its own bit (Instrumental = 64, Vocals = 128).
Co-authored-by: Florian Ostertag <flokuep@users.noreply.github.com>
