[BT] add `BetterTransformer` support for ViLT architecture (#508)
* add BetterTransfomer support for ViLT architecture
* fixed alphabetic order
* Update tests/bettertransformer/test_bettertransformer_vision.py
* Update tests/bettertransformer/test_bettertransformer_vision.py
Co-authored-by: Younes Belkada <49240599+younesbelkada@users.noreply.github.com>
Co-authored-by: Younes Belkada <49240599+younesbelkada@users.noreply.github.com>