Description of problem:

Validation fails when trying to delete the last network interface of a VM and multiqueue is enabled.

1. For example, create a VM from the rhel8 template, it comes up with this:
interfaces:

• macAddress: '02:aa:c2:00:00:00'
  masquerade: {}
  name: default
  networkInterfaceMultiqueue: true

2. Console -> Workloads -> Virtual Machines -> RHEL8 -> Network Interfaces -> NIC -> Delete
Error "virtio-net multiqueue request, but there are no virtio interfaces defined" for field "spec.template.spec.domain.devices.networkInterfaceMultiqueue".

3. Edit the yaml, removing just the interface from the list, but keeping 'networkInterfaceMultiqueue', same:
Error "virtio-net multiqueue request, but there are no virtio interfaces defined" for field "spec.template.spec.domain.devices.networkInterfaceMultiqueue".

4. Edit the yaml, remove 'networkInterfaceMultiqueue' and save. Now the user can delete the NIC via web console and also editing yaml manually.

Number of queues is per interface, if there are no interfaces just don't set the number of queues when passing the XML to libvirt, no need to make the user disable this just to manage interfaces (i.e. removing all pod interfaces and changing to multus bridge), then have to enable again at the end.

Version-Release number of selected component (if applicable):
4.9.3

How reproducible:
Always

Actual results:

• Cannot remove a network interface from a VM just created from builtin template.

Expected results:

• User able to remove network interface without editing yaml and figuring out errors