CI is broken after ruff-0.5.0: E721

[albertvillanova]

After ruff-0.5.0 release (https://github.com/astral-sh/ruff/releases/tag/0.5.0), our CI is broken due to E721 rule.

See: https://github.com/huggingface/datasets/actions/runs/9707641618/job/26793170961?pr=6983

src/datasets/features/features.py:844:12: E721 Use is and is not for type comparisons, or isinstance() for isinstance checks