fix: support video recording on iOS

[mario-deaconescu]

Closes #307

[alexandargyurov]

On Android, await CameraPreview.stopRecordVideo() returns {videoFilePath: string}
On iOS, await CameraPreview.stopRecordVideo() returns {value: string}

[alexandargyurov]

On iOS, CameraPreview.stopRecordVideo() seems to stop the camera, while on Android, the camera continues to be switched on.

[mario-deaconescu]

@alexandargyurov I fixed the mismatch between the return types. In what conditions does your camera turn off? From my testing, simply starting and stopping a recording does not stop the camera. If I display the video recording in the app, it stops, but that's because the video plays some audio, which causes the camera preview to pause until I hide the video again. This behavior does not happen if the video is muted, which leads me to believe that the audio playback is interfering with the audio recording part of the camera. In my opinion, this is a more general issue that does not concern this branch, but I might go look into it once/if this pr gets approved.

[qliqdev]

is it going to be merged?

[enisit]

@mario-deaconescu Good job adding this feature! I used this as a patch until this gets merged and discovered small issue with video output. Recorded videos longer than 10 seconds had issues with audio, basically video was playing ok but audio was not playing at all for longer videos. After some research I found that this is the issue https://stackoverflow.com/questions/26768987/avcapturesession-audio-doesnt-work-for-long-videos.
One solution is to change file extension to .mov and second option is to add this line
videoFileOutput?.movieFragmentInterval = CMTime.invalid
before calling videoFileOutput.startRecordingToOutputFileURL
It would be good to include either solution in the PR.

[mario-deaconescu]

I will look into this issue but I can't make any promises as I've got other projects going on. If you can solve the problem before me, I can let you merge the changes.

[mario-deaconescu]

I don't think changing the format of the video would have been a good option since .mov is not generally supported on the web, so I went with the other option. It seems to be fixed for now. If other issues come up, let me know.