fixes [`ExpansionTile` accessibility information doesn't read Expanded/Collapsed (iOS)](https://github.com/flutter/flutter/issues/132264)

### Code sample

<details>
<summary>expand to view the code sample</summary> 

```dart
import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        appBar: AppBar(
          title: const Text('ExpansionTile'),
        ),
        body: const ExpansionTile(
          title: Text("Title"),
          children: <Widget>[
            Placeholder(),
          ],
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () {},
          child: const Icon(Icons.add),
        ),
      ),
    );
  }
}
```

</details>

### Before

https://github.com/flutter/flutter/assets/48603081/542d8392-52dc-4319-92ba-215a7164db49

### After

https://github.com/flutter/flutter/assets/48603081/c9225144-4c12-4e92-bc41-4ff82b370ad7