UI: Add difficulty and failed_runs to admin_ui
- Adding difficulty param in admin UI so we can run the job in a light, medium, or heavy worker (It will change on job_type change event).
![image](https://github.com/huggingface/datasets-server/assets/5564745/2bf72734-2a8b-413c-b186-23418b68f8e8)

- Adding failed_runs in cache UI table
UI: Add difficulty and failed_runs to admin_ui: - Adding difficulty param in admin UI so we can run the job in a light, medium, or heavy worker (It will change on job_type change event).
![image](https://github.com/huggingface/datasets-server/assets/5564745/2bf72734-2a8b-413c-b186-23418b68f8e8)

- Adding failed_runs in cache UI table