notificationDaemon: Fix handling of image-path hint (#12778)

* notificationDaemon: fix incorrect assumption about image-path hint

Check if `image-path` is already a file URI before attempting conversion.

* fix: cleanup

* fix: missing argument gor GLib function

Author: UnFefeSauvage

js/ui/notificationDaemon.js

@@ -472,7 +472,12 @@ NotificationDaemon.prototype = {
                 image = St.TextureCache.get_default().load_from_raw(data, hasAlpha,
                                                                     width, height, rowStride, notification.IMAGE_SIZE);
             } else if (hints['image-path']) {
-                image = St.TextureCache.get_default().load_uri_async(GLib.filename_to_uri(hints['image-path'], null),
+                let image_path = hints['image-path'];
+                // Convert filepaths to file URIs but leave file URIs untouched
+                if (image_path.substr(0, 7) != 'file://') {
+                    image_path = GLib.filename_to_uri(image_path, null);
+                }
+                image = St.TextureCache.get_default().load_uri_async(image_path,
                                                                      notification.IMAGE_SIZE,
                                                                      notification.IMAGE_SIZE);
             }