Allow lazy loading thumbnail

Here is the patch

Hi purushotam.rai, I 've tested your patch it working as expected. I'm currently converting it to a MR.

Thanks!

Hi, I've applied the provided MR as a patch and it applied cleanly with no errors. Before applying the patch, there was no option for lazy loading for the video thumbnail in the field formatter of the field. And also there was no loading="lazy" attribute in the img tag. After applying the patch, user can enable/disable the lazyloading image for the field in the field formatter. On enabling the Lazy load images checkbox, the video thumbnail image is being loaded using lazyload and the loading="lazy" attribute has also been added in the img tag.
I've attached the before and after screenshots for reference and confirm that the provided MR is adding the new config for field formatter to enable/disable lazy loading for image.

Thanks!