Json builder: Allow features to override problematic Arrow types

### Feature request

In the JSON builder, use explicitly requested feature types before or while converting to Arrow.

### Motivation

Working with JSON datasets is really hard because of Arrow. At the very least, it seems like it should be possible to work-around these problems by explicitly setting problematic columns's types. But it seems like this is not possible because the features are only used *after* converting to arrow.

Here's a simple example where the Arrow error could potentially be avoided by converting the column to a string: https://colab.research.google.com/drive/16QHRdbUwKSrpwVfGwu8V8AHr8v2dv0dt?usp=sharing

### Your contribution

Maybe with some guidance. I'm not very familiar with arrow or pandas.