Iterable torch formatting
Used the TorchFormatter to get torch tensors in iterable dataset with format set to "torch".

It uses the data from Arrow if possible, otherwise applies recursive_tensorize.

When set back to format_type=None, cast_to_python_objects is used.

requires https://github.com/huggingface/datasets/pull/5821

close https://github.com/huggingface/datasets/issues/5793