Remove columns in interable dataset
### Feature request

Right now, remove_columns() produces a NotImplementedError for iterable style datasets

### Motivation

It would be great to have the same functionality irrespective of whether one is using an iterable or a map-style dataset

### Your contribution

hope and courage.
Transferring this issue as it's related to the 🤗 Datasets library  Hi @surya-narayanan! Could you provide some code snippet? This method has been recently added to the `IterableDataset`, so you need to update the `datasets`' installation (`pip install -U datasets`) to use it.