Fix null issue

lib/forez/ui/routes/forez_route.dart

@@ -37,6 +37,8 @@ class _MainRouteState extends MainController {
 
   @override
   Widget build(BuildContext context) {
+    if (forezGroup == null) return Text(tr("Missing Forez group!"));
+
     return StatusWidget(
       child: (c) => SafeArea(
         // Avoid OS areas