Ensure GtkFileChooserCell's type
Otherwise anything that dlopen()'s GTK will have a bad day.
See: https://discourse.gnome.org/t/strange-filechooserdialog-behaviour-in-gtk-4-10/14435
Otherwise anything that dlopen()'s GTK will have a bad day.
See: https://discourse.gnome.org/t/strange-filechooserdialog-behaviour-in-gtk-4-10/14435