Yo! So I was working through the Luna course and got stuck on this piece.
Luckily, checking the blenderArtists thread for the original "remove vertex groups" addon, it looks like a good samaritan has picked it up and updated it for 4.x. I tested it on my version (5.0.1) and it worked just fine.
The thread where the original is mentioned is https://blenderartists.org/t/batch-delete-vertex-groups-script/449881/2
You can skip the thread and pick it up over at https://radeonoff.gumroad.com/l/Gxkbp
Here's a short demo of me testing it out with my Luna rig at this stage:
