Added AppLifecycleState.hidden case (fixing build failure on Flutter 3.11.0-16.0.pre)

https://docs.flutter.dev/release/breaking-changes/add-applifecyclestate-hidden#migration-guide

lib/src/ui/reader_widget.dart

@@ -192,12 +192,14 @@ class _ReaderWidgetState extends State<ReaderWidget>
         break;
       case AppLifecycleState.inactive:
       case AppLifecycleState.paused:
+      case AppLifecycleState.hidden:
         controller?.dispose();
         setState(() {
           _isCameraOn = false;
         });
         break;
       case AppLifecycleState.detached:
+      default:
         break;
     }
   }