Full screen button does not work on iOS

Good morning,

I'm retrying this package after a year because I really need it. At the moment I'm using the plain `video_player` with a lot of handmade custom widget that are already included in `chewie`. After a year I see that there are yet a lot of issue with full screen button/mode.

In my case full screen button is still not working on iOS (iPhone XS). Are there any plans to fix the problem? On Android full screen seems to work perfectly.

```console
[✓] Flutter (Channel stable, 2.0.5, on macOS 11.2.3 20D91 darwin-x64, locale en-IT)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
[✓] Xcode - develop for iOS and macOS
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.1)
[✓] VS Code (version 1.55.2)
[✓] Connected device (5 available)

• No issues found!
```

```dart
@override
void initState() {
super.initState();

initalizeControllers();
}

void initalizeControllers() async {
_videoPlayerController = VideoPlayerController.network(widget.url);

await _videoPlayerController.initialize();

_chewieController = ChewieController(
videoPlayerController: _videoPlayerController,
autoPlay: false,
looping: false,
allowFullScreen: true,
allowPlaybackSpeedChanging: false);

if (widget.fullScreen) _chewieController.enterFullScreen();

if (!widget.fullScreen) await _chewieController.setVolume(0);

if (!widget.fullScreen) await _chewieController.setLooping(true);

if (widget.position != null)
await _chewieController.seekTo(widget.position);

if (widget.automaticStart) await _chewieController.play();

setState(() {});
}
```
```dart
@override
Widget build(BuildContext context) {
return _videoPlayerController.value.isInitialized
? ClipRRect(
borderRadius: BorderRadius.all(Radius.circular(
widget.fullScreen ? 0.0 : widget.previewCornerRadius)),
child: AspectRatio(
aspectRatio: _videoPlayerController.value.aspectRatio,
child: Scaffold(
backgroundColor: Colors.black,
body: Chewie(
controller: _chewieController,
),
),
),
)
: MyLoader();
}
```