🚨Fix MobileViT image processor default interpolation to BICUBIC (#43024)
* Fix MobileViT image processor default interpolation to BICUBIC
The original MobileViT implementation (Apple's ml-cvnets) and timm both
use BICUBIC interpolation for image preprocessing. Updates both slow and
fast image processors to match.
Contributes to #28180
* Remove copy substitution - code now matches source
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Co-authored-by: Yoni Gozlan <74535834+yonigozlan@users.noreply.github.com>