admin UI: automatically fill the steps list
Currently, the step `dataset-filetypes` is absent from the job types list

<img width="521" alt="Capture d’écran 2024-06-18 à 13 09 01" src="https://github.com/huggingface/dataset-viewer/assets/1676121/2fc31de2-63d9-46d2-81f8-cc79dc78e868">

The list should be created automatically from the processing graph + sorted alphabetically
admin UI: automatically fill the steps list: Currently, the step `dataset-filetypes` is absent from the job types list

<img width="521" alt="Capture d’écran 2024-06-18 à 13 09 01" src="https://github.com/huggingface/dataset-viewer/assets/1676121/2fc31de2-63d9-46d2-81f8-cc79dc78e868">

The list should be created automatically from the processing graph + sorted alphabetically