Check an object's abstract type's referenced or orphan_type status for visibility

[rmosolgo]

Fixes #4587

I hope ...

The challenge is, on the one hand:

• We need some way to add types to the schema to be used for loads:
• On the other hand, we have existing tests that say that orphan_types [...] isn't enough to make objects appear in results.

I think we'll need to track loads: references specifically 😩