Set to 'off' by default.
This will replace our intuiting the need to bust out when a hero class is applied with the
style classes dropdown. Someday, probably when we've moved beyond paragraphs, it would be
so nice to have configurations of the art direction options themselves, so that regular
usage is picking from a couple arranged options but there's an advanced option to get
more granular. But for now, we'll live with the editor having to understand how things
are supposed to work together.
