[gnome-shell] extensionSystem: Fix opening Extensions app from notification

[Marge Bot <marge-bot src gnome org>]

commit ddc2e0f4cb0046eac46a8ca7ddf53c39e386c3e4
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Jan 26 17:12:04 2021 +0100

    extensionSystem: Fix opening Extensions app from notification
    
    Launching the app is implemented by the source's open() method, but
    only external notifications are hooked up to call into the source
    when no default action was provided.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1595>

 js/ui/extensionSystem.js | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/js/ui/extensionSystem.js b/js/ui/extensionSystem.js
index 41ef98d70e..6b624fca09 100644
--- a/js/ui/extensionSystem.js
+++ b/js/ui/extensionSystem.js
@@ -252,6 +252,8 @@ var ExtensionManager = class {
             let notification = new MessageTray.Notification(source,
                 _('Extension Updates Available'),
                 _('Extension updates are ready to be installed.'));
+            notification.connect('activated',
+                () => source.open());
             source.showNotification(notification);
         }
     }