Fix `MacosPulldownMenuItem.onTap` doesn't open alert dialog

[TahaTesser]

fixes MacosPulldownMenuItem onTap doesnt call showMacosAlertDialog

Code sample

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```dart import 'package:flutter/cupertino.dart'; import 'package:macos_ui/macos_ui.dart'; void main() => runApp(const MyApp()); class MyApp extends StatelessWidget { const MyApp({super.key}); @override Widget build(BuildContext context) { return const MacosApp( debugShowCheckedModeBanner: false, home: HomePage(), ); } } class HomePage extends StatelessWidget { const HomePage({super.key}); @override Widget build(BuildContext context) { return MacosScaffold( toolBar: ToolBar( title: const Text('macos_ui'), actions: [ ToolBarPullDownButton( label: 'Actions', icon: CupertinoIcons.ellipsis_circle, tooltipMessage: 'Perform tasks with the selected items', items: [ MacosPulldownMenuItem( label: 'New Folder', title: const Text('New Folder'), onTap: () => showMacosAlertDialog( context: context, builder: (context) => MacosAlertDialog( appIcon: const FlutterLogo(size: 64), title: const Text('Title'), message: const Text('Message'), //horizontalActions: false, primaryButton: PushButton( controlSize: ControlSize.large, onPressed: Navigator.of(context).pop, child: const Text('Label'), ), ), ), ), MacosPulldownMenuItem( label: 'Open', title: const Text('Open'), onTap: () => debugPrint('Opening...'), ), ], ), ], ), ); } } ```

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Pre-launch Checklist

• [x] I have incremented the package version as appropriate and updated CHANGELOG.md with my changes
• [ ] I have added/updated relevant documentation
• [x] I have run "optimize/organize imports" on all changed files
• [x] I have addressed all analyzer warnings as best I could

[GroovinChip]

Just gonna run the checks manually since you're a first time contributor

[GroovinChip]

Looks like we've got some failing tests

[TahaTesser]

Looks like we've got some failing tests

For some reason test passes locally with FlutterLogo but not in the CI so i just replaced it.