windowManager: Do not shutdown ibus/xsettings on X11 compositor restart

These paths are meant for Xwayland, not for X11 compositors being restarted
through alt-f2 + r. Maybe some signal analogous to init-xserver should be
added for Xwayland shutdown paths, but this signal we are currently
listening for is backend agnostic.

Closes: https://gitlab.gnome.org/GNOME/gnome-shell/issues/2329

js/ui/windowManager.js

@@ -924,6 +924,8 @@ var WindowManager = class {
             return true;
         });
         global.display.connect('x11-display-closing', () => {
+            if (!Meta.is_wayland_compositor())
+                return;
             Shell.util_stop_systemd_unit('gsd-xsettings.target', 'fail');
             IBusManager.getIBusManager().restartDaemon();
         });