Stop relying on the NotificationCenter for removing delivered push notifications:

- this will improve the architecture but more importantly will remove some very flakey unit tests

ElementX/Sources/Services/Notification/Manager/NotificationManagerProtocol.swift

@@ -40,4 +40,7 @@ protocol NotificationManagerProtocol: AnyObject {
     func setUserSession(_ userSession: UserSessionProtocol?)
     
     func requestAuthorization()
+    
+    func removeDeliveredMessageNotifications(for roomID: String) async
+    func removeDeliveredInviteNotifications() async
 }