support for eager async preview urls (big videos)

[cjm771]

Hi awesome tool! i love it. realized for large videos preview url gif you try to generate gets 400'd due to automatic on the fly generation only works for file sizes 40mb and below. need to supply eager_async: true, so adding this slight change to your code would support it:

In the code put

if (image.resource_type === 'video') {
  if (image.eager?.length) {
    file.previewUrl = image.eager[0].secure_url;
  } else {
    file.previewUrl = cloudinary.url(`${image.public_id}.gif`, {
      video_sampling: 6,
      delay: 200,
      width: 250,
      crop: 'scale',
      resource_type: 'video',
    });
  }
}

example setting:

    actionOptions: {
          upload: {
            eager: [
              { video_sampling: 6,
                delay: 200,
                width: 250,
                crop: 'scale',
                resource_type: 'video',
                fetch_format: 'gif',
                format: 'gif',
              }
            ],
            eager_async: true,
          },
        }
      },