Some nmstate validations are skipped when NM config is in agent-config.yaml

When the user supplies nmstateConfig in agent-config.yaml invalid configurations may not be detected

4.12

every time

1. Create an invalid NM config. In this case an interface was defined with a route but no IP address 
2. The ISO can be generated with no errors
3. At run time the invalid was detected by assisted-service, create-cluster-and-infraenv.service logged the error "failed to validate network yaml for host 0, invalid yaml, error:"

Installation failed

Invalid configuration would be detected when ISO is created

It looks like the ValidateStaticConfigParams check is ONLY done when the nmstateconfig is provided in nmstateconfig.yaml, not when the file is generated (supplied in agent-config.yaml). https://github.com/openshift/installer/blob/master/pkg/asset/agent/manifests/nmstateconfig.go#L188