HTTP 400 Bad Request: Service level assign issue for virt-who content host or call API

Issue

• Modifying the service level for a virt-who content host via system purpose service level fail with HTTP 400 error code.
• Or call API to set the "auto-attach" value for a content host on WEI UI
  e.g.

# curl -H "Accept:application/json,version=2" -H "Content-Type:application/json" -X PUT -u admin:password -k -d "{\"host\":{\"subscription_facet_attributes\":{\"autoheal\":\"false\"}}}" https://satellite.example.com/api/v2/hosts/content-host.example.com

{
  "error": {"message":"Katello::Resources::Candlepin::Consumer: 400 Bad Request {\"displayMessage\":\"Runtime Error com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `org.candlepin.dto.api.v1.GuestIdDTO` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('xxxx')\\n at [Source: (org.candlepin.servlet.filter.logging.TeeHttpServletRequest$1); line: 1, column: 179] (through reference chain: org.candlepin.dto.api.v1.ConsumerDTO[\\\"guestIds\\\"]->java.util.ArrayList[0]) at com.fasterxml.jackson.databind.exc.MismatchedInputException.from:63\",\"requestUuid\":\"xxxx\"} (PUT /candlepin/consumers/xxxx)"}
}