Configurations in yaml not working

### Dataset configurations cannot be created in YAML/README

Hello! I'm trying to follow the docs here in order to create structure in my dataset as added from here (#5331): https://github.com/huggingface/datasets/blob/8b8e6ee067eb74e7965ca2a6768f15f9398cb7c8/docs/source/repository_structure.mdx#L110-L118

I have the exact example in my config file for [my data repo](https://huggingface.co/datasets/tsor13/test):
```
configs:
- config_name: main_data
data_files: "main_data.csv"
- config_name: additional_data
data_files: "additional_data.csv"
```

Yet, I'm unable to load different configurations:
```
from datasets import get_dataset_config_names
get_dataset_config_names('tsor13/test', use_auth_token=True)
```
returns a single split, `['tsor13--test']`

Does anyone have any insights?

@polinaeterna thank you for adding this feature, it is super useful. Do you happen to have any ideas?

### Steps to reproduce the bug

from datasets import get_dataset_config_names
get_dataset_config_names('tsor13/test')

### Expected behavior

I would expect there to be two splits, `main_data` and `additional_data`. However, only `['tsor13--test']` test is returned.

### Environment info

- `datasets` version: 2.14.4
- Platform: macOS-13.4-arm64-arm-64bit
- Python version: 3.11.4
- Huggingface_hub version: 0.16.4
- PyArrow version: 12.0.1
- Pandas version: 1.5.1