Cover Art Search Doesn't Work

[Mou5e]

The "Change cover art" page doesn't work for me. Instead of images showing up, I get a message that says "Please wait..." and the javascript console shows "Uncaught TypeError: coverArtService.searchCoverArt is not a function".
This broke a couple months back and wasn't fixed when I upgraded to 6.0.beta2. Any ideas on what I can do to fix this?