transformers

12048990 - Add new dim to `num_items_in_batch` if necessary (#36967)

Add new dim to `num_items_in_batch` if necessary (#36967) * Add new dim to `num_items_in_batch` if necessary * Unsqueeze only in the DP case --------- Co-authored-by: Ilyas Moutawwakil <57442720+IlyasMoutawwakil@users.noreply.github.com> Co-authored-by: Marc Sun <57196510+SunMarc@users.noreply.github.com> Co-authored-by: Yih-Dar <2521628+ydshieh@users.noreply.github.com>