Can delete notifications from notifications screen

lib/helpers/notifications_helper.dart

@@ -75,4 +75,14 @@ class NotificationsHelper {
                       f["from_container_type"]]))
           .toList());
   }
+
+  /// Mark a notification as seen
+  Future<bool> markSeen(Notification n) async => (await APIRequest(
+        uri: "notifications/mark_seen",
+        needLogin: true,
+        args: {
+          "notifID": n.id.toString(),
+        },
+      ).exec())
+          .isOK;
 }