This differential introduces changes that are supposed to test theory described in: https://linear.app/comm/issue/ENG-4886/nse-error-during-notif-decryption-bad-message-mac#comment-5864be25
Assuming that NSE restarts notification processing even after relevant contentHandler was called then originally displayed notification should overwrite original one. However if instead of using contentHandler to display error message notification we schedule error message notification as local notification then this shouldn't happen.
Before scheduling error message notification we also check if notification with the same isn't already displayed. It should further support theory.