Dataset Viewer issue for cbt and "raw" configuration: Cannot GET
### Link

https://huggingface.co/datasets/cbt

### Description

There is an issue with the URL to show a specific split for the "raw" configuration:
```
Cannot GET /datasets/cbt/viewer/raw/train
``` 
- See: https://huggingface.co/datasets/cbt/viewer/raw/train

However, it works when no split name is provided in the URL.
- See: https://huggingface.co/datasets/cbt/viewer/raw

Maybe the word "raw" has a special meaning in the URL and cannot be used as configuration name (as it is the case in GitHub)?

CC: @severo 
Dataset Viewer issue for cbt and "raw" configuration: Cannot GET: ### Link

https://huggingface.co/datasets/cbt

### Description

There is an issue with the URL to show a specific split for the "raw" configuration:
```
Cannot GET /datasets/cbt/viewer/raw/train
``` 
- See: https://huggingface.co/datasets/cbt/viewer/raw/train

However, it works when no split name is provided in the URL.
- See: https://huggingface.co/datasets/cbt/viewer/raw

Maybe the word "raw" has a special meaning in the URL and cannot be used as configuration name (as it is the case in GitHub)?

CC: @severo 