PopupImageMenuItems used to position the icon after the label, so we ended up with our own icon+label items. However the icon position was changed years ago in the shell, so inherit from PopupImageMenuItem instead. This does not only simplify the code a bit, but also pulls in features we are currently missing, like a11y labelling. Closes: https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/issues/542