Add confirm=? query-param to delete-user route and confirm dialog in flutter [skip-tests]

flutter/lib/state/app_auth.dart

@@ -225,6 +225,10 @@ class AppAuth extends ChangeNotifier implements TokenSource {
     return _tokenAdmin!;
   }
 
+  String? getTokenOrNull() {
+    return _tokenAdmin;
+  }
+
   @override
   String getUserID() {
     return _userID!;

flutter/lib/state/app_theme.dart

@@ -1,4 +1,3 @@
-import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:simplecloudnotifier/state/globals.dart';