### What?
This PR adds a new `admin.disableRowTypes` config to `'join'` fields
which hides the `"Type"` column from the relationship table.
### Why?
While the collection type column _can be_ helpful for providing
information, it's not always necessary and can sometimes be redundant
when the field only has a singular relationTo. Hiding it can be helpful
by removing visual noise and providing editors the data directly.
### How?
By threading `admin.disableRowTypes` directly to the `getTableState`
function of the `RelationshipTable` component.
**With row types** (via `admin.disableRowTypes: false | undefined` OR
default for polymorphic):
**Without row types** (default for monomorphic):
