DownloadConfig.proxies not work when load_dataset_builder calling HfApi.dataset_info  
### Describe the bug

```python
download_config = DownloadConfig(proxies={'https': '<my proxy>'})
builder = load_dataset_builder(..., download_config=download_config)
```
But, when getting the dataset_info from HfApi, the http requests not using the proxies.

### Steps to reproduce the bug

1. Setup proxies in DownloadConfig.
2. Call `load_dataset_build` with download_config.
3. Inspect the call stack in HfApi.dataset_info.

![image](https://github.com/huggingface/datasets/assets/138426806/33e538a8-2e22-4e63-b634-343febe5324b)

### Expected behavior

DownloadConfig.proxies works for getting dataset_info.

### Environment info

https://github.com/huggingface/datasets/commit/406b2212263c0d33f267e35b917f410ff6b3bc00
Python 3.11.4