transformers

27c79a0f - Enable instantiating model with pretrained backbone weights (#28214)

Enable instantiating model with pretrained backbone weights (#28214) * Enable instantiating model with pretrained backbone weights * Update tests so backbone checkpoint isn't passed in * Remove doc updates until changes made in modeling code * Clarify pretrained import * Update configs - docs and validation check * Update src/transformers/utils/backbone_utils.py Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com> * Clarify exception message * Update config init in tests * Add test for when use_timm_backbone=True * Small test updates --------- Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>