FdoNotificationDaemon: Emit ActivationToken before ActionInvoked signal

Two years ago FDO notifications spec gained the ability to pass an
activation token (often called startup id) let's finally implement it.

See: b9a470004d

Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/358
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3199>

js/dbusServices/notifications/notificationDaemon.js

@@ -27,6 +27,14 @@ export const NotificationDaemon = class extends ServiceImplementation {
                     log(error.message);
             });
 
+        this._proxy.connectSignal('ActivationToken',
+            (proxy, sender, params) => {
+                const [id] = params;
+                this._emitSignal(
+                    this._activeNotifications.get(id),
+                    'ActivationToken',
+                    new GLib.Variant('(us)', params));
+            });
         this._proxy.connectSignal('ActionInvoked',
             (proxy, sender, params) => {
                 const [id] = params;