Fallback sushy-emulator to public net if no ctlplane

If ctlplane network is not enabled/attached to the controller-0 node
fallback the sushy.utility host record to the public net.

This allows me to configure controller with only public net:

```
cifmw_libvirt_manager_configuration:
  vms:
    controller:
      nets:
        - ocpbm

cifmw_networking_definition:
  instances:
    controller-0:
      networks: {}
```

Author: hjensas

roles/reproducer/tasks/prepare_networking.yml

@@ -216,8 +216,8 @@
               - "sushy.utility"
               - "controller-0.utility"
             ips:
-              - "{{ _controller_net.ctlplane.ip_v4 | default('') }}"
-              - "{{ _controller_net.ctlplane.ip_v6 | default('') }}"
+              - "{{ _controller_net.ctlplane.ip_v4 | default(_controller_net[_pub_net].ip_v4) | default('') }}"
+              - "{{ _controller_net.ctlplane.ip_v6 | default(_controller_net[_pub_net].ip_v6) | default('') }}"
             state: present
       ansible.builtin.include_role:
         name: "dnsmasq"