Changes to List Backends

added the optional property backends/items/router_client_address to the response with the 200 status

response property backends/items/last_heartbeat list-of-types was widened by adding types null to media type application/json of response 200

response property backends/items/node_conditions/rules list-of-types was widened by adding types null to media type application/json of response 200

the backends/items/scheduler_settings/scheduler_type response's property type changed from no type to string for status 200

added the new kai enum value to the backends/items/scheduler_settings/scheduler_type response property for the response status 200

removed BackendSchedulerType from the backends/items/scheduler_settings/scheduler_type response property allOf list for the response status 200

the response's body type changed from string to object for status 200

added the required property backends to the response with the 200 status