Add two fields to /splits
(edit)

add fields `num_bytes` and `num_examples` to the `/splits` response. The data comes from DatasetInfo, or `null` (see https://github.com/huggingface/datasets-preview-backend#splits)

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<strike>Being able to retrieve a dataset infos via an HTTP API will be valuable for AutoNLP</strike>

Add two fields to /splits: (edit)

add fields `num_bytes` and `num_examples` to the `/splits` response. The data comes from DatasetInfo, or `null` (see https://github.com/huggingface/datasets-preview-backend#splits)

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<strike>Being able to retrieve a dataset infos via an HTTP API will be valuable for AutoNLP</strike>
