The search API doesn't seem to be returning data for customers right now. Once it works for customers, we should switch all this stuff to be customers.

If you want to debug search for customers, here's a search URI for my marketplace that returns no data: https://auth.balancedpayments.com/v1/marketplaces/TEST-MP5m04ORxNlNDm1bB7nkcgSY/search?limit=10&offset=0&type=customer

Same query with `type=account` returns plenty of data.