resize_token_embeddings in BartForConditionalGeneration doesn't change lm_head size
### System Info

```shell
- `transformers` version: 4.19.2
- Platform: Windows-10-10.0.19041-SP0
- Python version: 3.7.6
- Huggingface_hub version: 0.1.2
- PyTorch version (GPU?): 1.11.0+cu113 (True)
- Tensorflow version (GPU?): not installed (NA)
- Flax version (CPU?/GPU?/TPU?): not installed (NA)
- Jax version: not installed
- JaxLib version: not installed
- Using GPU in script?: Y
- Using distributed or parallel set-up in script?: N
```


### Who can help?

@patil-suraj

### Information

- [ ] The official example scripts
- [X] My own modified scripts

### Tasks

- [ ] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [X] My own task or dataset (give details below)

### Reproduction

1. Call resize_token_embeddings with different vocab size

### Expected behavior

```shell
When I call resize_token_embeddings, it resizes embedding but not lm_head even though embedding and lm_head are tied.
Is it intended or a bug?
Or am I using resize_token_embeddings method wrongly?
```

I am wrong about this issue.
It works fine.