Fix LoadBalance, Relay load error

lib/models/app.dart

@@ -107,7 +107,7 @@ class AppState with ChangeNotifier {
     } else {
       final index = groups.indexWhere((element) => element.name == proxyName);
       if (index == -1) return type;
-      return "$type(${groups[index].now})";
+      return "$type(${groups[index].now ?? '*'})";
     }
   }
 

lib/models/generated/proxy.g.dart

@@ -28,6 +28,8 @@ const _$GroupTypeEnumMap = {
   GroupType.Selector: 'Selector',
   GroupType.URLTest: 'URLTest',
   GroupType.Fallback: 'Fallback',
+  GroupType.LoadBalance: 'LoadBalance',
+  GroupType.Relay: 'Relay',
 };
 
 _$ProxyImpl _$$ProxyImplFromJson(Map<String, dynamic> json) => _$ProxyImpl(