Description of problem:

While changing the SLA for a hypervisors, it fails with the below errors.

---------
 The host virt-who.example.com does not exist or there are access permissions needed. Please contact your administrator if this issue continues.

Katello::Resources::Candlepin::Consumer: 400 Bad Request

{"displayMessage":"Runtime Error com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.ArrayList<org.candlepin.dto.api.server.v1.EnvironmentDTO>` from String value (token `JsonToken.VALUE_STRING`)\n at [Source: (org.candlepin.servlet.filter.logging.TeeHttpServletRequest$1); line: 1, column: 112] (through reference chain: org.candlepin.dto.api.server.v1.ConsumerDTO[\"environments\"]) at com.fasterxml.jackson.databind.exc.MismatchedInputException.from:59","requestUuid":"27791679-a878-4ddf-bbb1-4d76efafa4f7"}

(PUT /candlepin/consumers/76d5fbe9-8070-45ec-bbca-d7f6428b1ace)
-------

How reproducible:

  Hosts --> Content hosts --> virt-who.example.com --> Overview --> System purpose --> SLA --> Select any --> Save

Is this issue a regression from an earlier version:

 Observed on Satellite 6.14 and 6.15 and it works as expected in 6.13

DEV Tracker for https://issues.redhat.com/browse/SAT-28552