Fixes app orientation to vertical for mobile phones

lib/main.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:just_audio_background/just_audio_background.dart';
-
+import 'package:flutter/services.dart';
 import 'app_theme_business_object.dart';
 import 'live_info_business_object.dart';
 import 'live_info_panel.dart';
@@ -14,6 +14,12 @@ Future<void> main() async {
     androidNotificationOngoing: true,
   );
 
+  WidgetsFlutterBinding.ensureInitialized();
+  await SystemChrome.setPreferredOrientations([
+    DeviceOrientation.portraitUp,
+    DeviceOrientation.portraitDown,
+  ]);
+
   runApp(const MyApp());
 }