Remove beta from dark theme name ref #16076 (#16253)
Remove beta from dark theme name ref #16076 (#16253)

Remove beta from dark theme name ref #16076
nextcloud/server,andreas-p/nextcloud-server,andreas-p/nextcloud-server,nextcloud/server,andreas-p/nextcloud-server,andreas-p/nextcloud-server,nextcloud/server,andreas-p/nextcloud-server,nextcloud/server