Bump SDK bindings to v26.09.3 (#7637)

Fix API breaks:

- A new `Mentions` room list filter is available.
- `RoomListService.subscribeToRooms` is now `RoomListService.setRoomSubscriptions`.
- `enableAutomaticBackPagination` moved from `Client` to `ClientBuilder`.

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/roomlist/RoomListFilter.kt

@@ -48,10 +48,15 @@ sealed interface RoomListFilter {
     ) : RoomListFilter
 
     /**
-     * A filter that matches rooms that are unread.
+     * A filter that matches rooms that has unread notifications.
      */
     data object Unread : RoomListFilter
 
+    /**
+     * A filter that matches rooms that have unread mentions.
+     */
+    data object Mentions : RoomListFilter
+
     /**
      * A filter that matches rooms that are marked as favorite.
      */