Fix/video classification pipeline video processor (#46256)
* fix(pipelines): add video processor support to VideoClassificationPipeline
VideoClassificationPipeline previously hardcoded _load_image_processor=True,
causing an OSError when loading models that only have a video processor
(e.g. facebook/vjepa2-vitl-fpc64-256).
- Add _load_video_processor flag support to pipeline base classes
- Add _resolve_video_processor helper in pipelines/__init__.py
- Update VideoClassificationPipeline to load both processors optionally,
preferring video_processor when available, falling back to image_processor
for legacy models (VideoMAE, ViViT, TimeSformer)
Fixes #41950
* Add VideoProcessor classes for timesformer and vivit
* Add video processor tests for timesformer and vivit
* Add docs entries for TimesformerVideoProcessor and VivitVideoProcessor
* Address PR review comments on pipeline video processor loading
* Add video_processor to pipeline() overload stubs
* Improve deprecation warning wording for image_processor fallback
* load the video via processor
* fix repo
---------
Co-authored-by: raushan <raushan@huggingface.co>
