fix: 🐛 pass token when retrieving the split names
Currently, it does not work with https://huggingface.co/datasets/mozilla-foundation/common_voice_7_0/blob/main/common_voice_7_0.py#L146 (which was the goal), because `dl_manager.download_config.use_auth_token` is ignored, and the authentication is required to be use `huggingface-cli login`.
In my use case (dataset viewer), I'd prefer to use a specific "User Token Access", with only the "read" role (https://huggingface.co/settings/token).

See https://github.com/huggingface/datasets-preview-backend/issues/74#issuecomment-1007316853 for the context > Simply passing download_config is ok :)

hmm, I prefer only passing use_auth_token. But the question is more: is it correct, in the (convoluted) case if `download_config.use_auth_token` exists and is different from `use_auth_token`? Which one should be used? If both are passed, `use_auth_token` should have the priority (more specific parameters have the higher priority)