dbusServices: Always import dbus errors

This makes sure custom errors are registered correctly, even when
the service doesn't do anything other than passing them on.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3159>

js/dbusServices/dbusService.js

@@ -3,6 +3,8 @@ import GLib from 'gi://GLib';
 
 import {programArgs} from 'system';
 
+import './misc/dbusErrors.js';
+
 const Signals = imports.signals;
 
 const IDLE_SHUTDOWN_TIME = 2; // s