[Notifications] Disable history check box when notifications are disabled
You cannot have a history of notifications if you don't get any notifications in the first place.
Also move checkbox below notification history as it's semantically related.
Differential Revision: https://phabricator.kde.org/D9979
(cherry picked from commit c81a0151f50ef03ecfe8bea2d331af9e74cdb63f)