Preserve non-`input_colums` in `Dataset.map` if `input_columns` are specified
_The documentation is not available anymore as the PR was closed or merged._
Currently, if the `input_columns` list in `Dataset.map` is specified, the columns not in that list are dropped after the `map` transform.

This makes the behavior inconsistent with `IterableDataset.map`.
 
(It seems this issue was introduced by mistake in https://github.com/huggingface/datasets/pull/2246) 

Fix https://github.com/huggingface/datasets/issues/4858