🐛 Buping Hyrax to resolve CSV export

[jeremyf]

From Bulkrax commit:

Prior to this commit, when exporting a FileSet and GenericWork we'd
see a "creator_1" and "creator" column. The "creator" column might
look as follows: ["Sandra Samvera"]. Which meant that creator was
not an ActiveTriples::Relation (based on the prior logic). Yet the
"creator" field was stored as multi-value. Perhaps having been
previously coerced into an Array.

With this commit, we're favoring the Bulkrax parser field mapping
"join" configuration over whether or not the object is an
=ActiveTriples::Relation=. That is to say, if you told us to join the
field, we're going to do that regardless of the data we have.

Likewise, if the field's value is not an enumerable, we're not going
to introduce an ordinal suffix (e.g. "creator_1" when we have a scalar
creator).

In other words don't do the join logic if we don't have an "array" or
we weren't told to join arrays.

Perhaps we could interrogate the model to ask if it's single value or
not? But this reduces the implementation knowledge of the properties
by looking at a more primitive level (is the data multi-valued or
not).

Related to:

• 🐛 Normalizing export column names samvera/bulkrax#847
• Export Format issue #624