Agent based Installer fails with error `err_msg: Invalid YAML string: unknown field route-type` while using route-type as blackhole.

Issue

• After booting the cluster nodes with the agent iso, the installation fails with error err_msg: Invalid YAML string: unknown field route-type.

• The following error logs message can be seen in journalctl of the rendezvous host.

WARNING     * failed to validate network yaml for host 0, nmstate GenerateConfiguration failed, error: failed when generating the configuration {"dns-resolver":{"config":{"server":["x.x.x.x"]}},"interfaces":[{"ipv4":{"address":[{"ip":"x.x.x.x","prefix-length":28}],"dhcp":false,"enabled":true},"ipv6":{"enabled":false},"mac-address":"x:x:x:x:x:x","name":"<interface>","state":"up","type":"ethernet"}],"routes":{"config":[{"destination":"0.0.0.0/0","next-hop-address":"x.x.x.x","next-hop-interface":"<interface>"},{"destination":"x.x.x.x/x","route-type":"blackhole"}]}} with rc: 1, err_msg: Invalid YAML string: unknown field route-type, expected one of state, destination, next-hop-interface, next-hop-address, metric, table-id, weight, err_kind: InvalidArgument