Test get_dataset_config_info with non-existing/gated/private dataset
Test get_dataset_config_info with non-existing/gated/private dataset.

Related to:
- #7109

See also:
- https://github.com/huggingface/dataset-viewer/pull/3037: https://github.com/huggingface/dataset-viewer/pull/3037/commits/bb1a7e00c53c242088597cab6572e4fd57797ecb