[extractor/youtube] Fix `:ytnotifications` extractor (#3775)

Still some issues, see https://github.com/yt-dlp/yt-dlp/pull/3775

Authored by: coletdjnz

yt_dlp/extractor/youtube.py

@@ -5673,11 +5673,13 @@ class YoutubeNotificationsIE(YoutubeTabBaseInfoExtractor):
         channel = traverse_obj(
             notification, ('contextualMenu', 'menuRenderer', 'items', 1, 'menuServiceItemRenderer', 'text', 'runs', 1, 'text'),
             expected_type=str)
+        notification_title = self._get_text(notification, 'shortMessage')
+        if notification_title:
+            notification_title = notification_title.replace('\xad', '')  # remove soft hyphens
+        # TODO: handle recommended videos
         title = self._search_regex(
-            rf'{re.escape(channel)} [^:]+: (.+)', self._get_text(notification, 'shortMessage'),
+            rf'{re.escape(channel or "")}[^:]+: (.+)', notification_title,
             'video title', default=None)
-        if title:
-            title = title.replace('\xad', '')  # remove soft hyphens
         upload_date = (strftime_or_none(self._extract_time_text(notification, 'sentTimeText')[0], '%Y%m%d')
                        if self._configuration_arg('approximate_date', ie_key=YoutubeTabIE.ie_key())
                        else None)