chore: dart 3+

lib/data/model/app/update.dart

@@ -133,9 +133,7 @@ class AppUpdatePlatformSpecific<T> {
         return linux;
 
       /// Not implemented yet.
-      case OS.web:
-      case OS.fuchsia:
-      case OS.unknown:
+      case OS.web || OS.fuchsia || OS.unknown:
         return null;
     }
   }

lib/data/provider/server.dart

@@ -325,7 +325,7 @@ class ServerProvider extends ChangeNotifier {
           Loggers.app.warning('Write script to ${spi.name} failed', e);
           return;
         } finally {
-          await file.delete();
+          if (await file.exists()) await file.delete();
         }
       }
     }