Change hide_test:bool to hiding displayed metrics, not preventing evaluation form happening.

[aiqc]

Difficulty: ★☆☆☆☆

Background

When using a validation split/fold to prevent evaluation bias top tune parameters/ topologies, you're not supposed to look at the holdout set.

Problem

Currently, the hide_test=True argument can be set when creating a Batch. However, this prevents the metrics from being generated on the test split entirely.

Solution

• It would be better to have an argument on plot and metric functions for hiding the test split from the displayed data.