Support JSON file with an array of strings

[albertvillanova]

Support loading a dataset from a JSON file with an array of strings.

See: https://huggingface.co/datasets/CausalLM/Refined-Anime-Text/discussions/1

[severo]

https://huggingface.co/datasets/CausalLM/Refined-Anime-Text/discussions/1 has been fixed, but how can we check if there are other datasets with the same error, in datasets-server's database? I don't know how to get the list of erroneous cache entries, since we only copied Error code: JobManagerCrashedError, but not the traceback in details... Do you remember the error message, or the underlying exception, we had?