Remove leftover `uploads/appearance` symlink
While cleaning up the symlinks that kept the files available during the deploy, we missed cleaning up the appearance folder because of a typo.. The folder still needs to be cleaned up because if someone would create a group with full patch
appearance/header_logo the images stored in those locations could get lost.
This was started in #33359 (closed) but needs to be backported (to 9.0, 9.1 & 9.2) because the symlink is causing issues with backups.