Revert "Add is_trakt_group field to PlaylistGroup and update sorting logic"

This reverts commit 27d84edf9c.

backend/src/processing/processor/trakt.rs

@@ -206,7 +206,6 @@ fn create_category_from_matches<'a>(
         title: String::from(group_title),
         channels: matched_items,
         xtream_cluster: cluster,
-        is_trakt_group: true,
     })
 }