Compression crash (v2.1.1)

Hi,
On IOS, picking a video from library; then trying to compress it crash app

```dart
final MediaInfo mediaInfo = await VideoCompress.compressVideo(
widget.path,
quality: VideoQuality.MediumQuality,
deleteOrigin: false,
includeAudio: true);
```

```dart
Error : Invalid argument(s) (path): Must not be null
```
i double check, path is never null and exists.
adding some logging show that

```dart
At some point, data is erased, and it remain only ::
{"isCancel":false}
```
v2.1.1 should correct this according some issue, but its not my case.
Thanks, Nelson

Edit:
Video is picked from library [(https://github.com/CaiJingLong/flutter_photo_manager)](https://github.com/CaiJingLong/flutter_photo_manager).
It worked when video is record from camera, but crash when picking from library