Graphics folder-cleaning functions no longer working

[alykat]

When I move graphics from the graphics archive to graphics-archive and other users pull the updated graphics repo, there are a number of .gitignored files from the archived graphics that still exist in folks' directories.

Historically, we've advised users to run these git clean commands to remove those stray folders:
https://github.com/nprapps/dailygraphics#keeping-the-graphics-directory-clean

Alice and Danielle report that, after my most recent round of archiving, the folder-cleaning instructions here no longer work for them, and the stray folders still exist.