Fix unexpected `position_ids` keys when loading OwlViT models (#44508)
* Fix unexpected `position_ids` keys when loading OwlViT models
Older OwlViT checkpoints saved `position_ids` as buffers in the text and
vision embedding modules. These tensors are simple integer ranges and are
now recomputed dynamically during initialization.
This results in `UNEXPECTED` key warnings when loading models such as
`google/owlvit-base-patch32`.
Add the corresponding patterns to `_keys_to_ignore_on_load_unexpected`
to suppress these warnings.
* Fix OwlViT copy consistency for owlv2