Music videos are detected as ads

[donbex]

Some playlists, e.g. this one include music videos. However, blockify erroneously detects them as ads and mutes them. This is probably because they have an empty artist metadata field, e.g.

$ playerctl metadata
spotify mpris:trackid             spotify:episode:61u1uwI2nJehLtEJlvEMX9
spotify mpris:length              227750000
spotify mpris:artUrl              
spotify xesam:album               Hot Country: The Performances
spotify xesam:albumArtist         
spotify xesam:artist              
spotify xesam:autoRating          0.0
spotify xesam:discNumber          0
spotify xesam:title               Morgan Wallen - Whiskey Glasses (Live)
spotify xesam:trackNumber         0
spotify xesam:url                 https://open.spotify.com/episode/61u1uwI2nJehLtEJlvEMX9