Remove extra `label` column
In example dataset https://huggingface.co/datasets/datasets-examples/doc-audio-4, we have an "unexpected" label column with only `null` values.

<img width="676" alt="Capture d’écran 2024-08-02 à 12 33 10" src="https://github.com/user-attachments/assets/e8e8a4b9-4681-4bb0-b8b4-31e4b0373a0d">

I think it's due to a "collision" between the heuristics that define splits and/or classes based on the directories. There is a `drop_labels=True` option in the datasets library, if it helps.

Ideally, in this case, we should have two splits (train and test), and no additional `label` column.

I think the issue also exists with image datasets.
Remove extra `label` column: In example dataset https://huggingface.co/datasets/datasets-examples/doc-audio-4, we have an "unexpected" label column with only `null` values.

<img width="676" alt="Capture d’écran 2024-08-02 à 12 33 10" src="https://github.com/user-attachments/assets/e8e8a4b9-4681-4bb0-b8b4-31e4b0373a0d">

I think it's due to a "collision" between the heuristics that define splits and/or classes based on the directories. There is a `drop_labels=True` option in the datasets library, if it helps.

Ideally, in this case, we should have two splits (train and test), and no additional `label` column.

I think the issue also exists with image datasets.