reduce test length to 24 hours

management/lib/widgets/user_view.dart

@@ -214,7 +214,7 @@ class _UserViewState extends State<UserView> {
     var date = form.certificationDate;
     var time = form.certificationTime;
     if (form.isTested) {
-      date = DateTime(date!.year, date.month, date.day).add(const Duration(hours: 48));
+      date = DateTime(date!.year, date.month, date.day).add(const Duration(hours: 24));
       date = date.add(Duration(hours: time!.hour, minutes: time.minute));
     } else if (form.isRecovered) {
       if (DateTime.now().difference(date!) < const Duration(days: 29)) {