An array of objects with a field that is not always present does not have to be marked as optional

When a request or response is being documented that contains an array of objects, and those objects have a field that is not always present, the field should have to be marked as optional for the test to pass. That's not the case at the moment. As things stand, as long as the field is present in at least one of the objects in the array, the test will pass.