Optional Content Warning for Datasets
**Is your feature request related to a problem? Please describe.**
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We now have hate speech datasets on the hub, like this one: https://huggingface.co/datasets/HannahRoseKirk/HatemojiBuild

I'm wondering if there is an option to select a content warning message that appears before the dataset preview? Otherwise, people immediately see hate speech when clicking on this dataset.

**Describe the solution you'd like**
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Implementation of a content warning message that separates users from the dataset preview until they click out of the warning.

**Describe alternatives you've considered**
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Possibly just a way to remove the dataset preview completely? I think I like the content warning option better, though.

**Additional context**
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