Tests parameterize models directly with dicts, not pydantic models, which are reserved for API calls

Incomplete, but replacing manual status code assertions with assertion methods of TestServerBaseClass

Removed model_id from Model objects, which in any case in managed by session.  But tests aren't passing; need to investigate further.

Working functionally but still need to verify that bounding box-generated RoiSet matches content of one with segmentation;

Parameterized deprojection when creating RoiSet from binary mask, including option to pass a channel