Fix `resize_token_embeddings` (#26861) (#26865)
* Fix `resize_token_embeddings` about `requires_grad`
The method `resize_token_embeddings` should keep `requires_grad`
unchanged for all parameters in embeddings.
Previously, `resize_token_embeddings` always set `requires_grad`
to `True`. After fixed, `resize_token_embeddings` copy the
`requires_grad` attribute in the old embeddings.