gnome-shell-extension-prefs should be deprecated in Jammy

Since upgrading to Jammy, I've noticed that we have available the package "gnome-shell-extension-manager" which does everything "gnome-shell-extension-prefs" does, plus it allows to do extension installations.

Not only should "gnome-shell-extension-prefs" be deprecated (because we now have two similar apps with two similar icons doing almost the same thing), we should also remove some dependencies that other packages have to "prefs". Per example, "gnome-shell-extensions".