This was forgotten when porting to GTK 4, leading to the following error
when user tries to copy the error message produced by an extension:
JS ERROR: TypeError: Gtk.Clipboard is undefined
_initActions/<@resource:///org/gnome/Shell/Extensions/js/extensionsService.js:255:31
run@resource:///org/gnome/Shell/Extensions/js/dbusService.js:177:20
main@resource:///org/gnome/Shell/Extensions/js/main.js:19:13
run@resource:///org/gnome/gjs/modules/script/package.js:206:19
start@resource:///org/gnome/gjs/modules/script/package.js:190:8
@/nix/store/fwnkwvhwm3kqck4fhkc5y5z853radggg-gnome-shell-40.0/share/gnome-shell/.org.gnome.Shell.Extensions-wrapped:7:17
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1795>
1b5d71130e