Add video modality for InstrucBLIP (#30182)
* squash in single commit
* add docs
* dummy obj
* more changes in diff converter
* tiny fix
* make docs happy
* skip test
* repo consistency tests
* update docstring
* style
* fix tests
* change diff imports
* [run-slow] instructblipvideo
* [run-slow] instructblipvideo
* fix tests and remove logit check
* [run-slow] instructblipvideo
