Description of problem:
One of the conditions of hot-plugging an interface is the existence of a backing NetworkAttachmentDefinition, but this action succeeds even if this resource doesn't exist.

Version-Release number of selected component (if applicable):
CNV 4.14.0

How reproducible:
Always

Steps to Reproduce:
1. Create and run a basic VM (no secondary NICs).
$ oc create ns yoss-ns
namespace/yoss-ns created
$ oc project yoss-ns
Now using project "yoss-ns" on server "https://api.net-ys-414o.rhos-psi.cnv-qe.rhood.us:6443".
$ oc apply -f vm-fedora.yaml
virtualmachine.kubevirt.io/vm-fedora created
$ virtctl start vm-fedora
VM vm-fedora was scheduled to start

2. Create a bridge interface over one of the nodes secondary NICs using a NodeNetworkConfigurationPolicy.
$ oc apply -f nncp-linux-bridge.yaml
oc get nncp -w
nodenetworkconfigurationpolicy.nmstate.io/hotplug-linux-bridge created
ysegev@ysegev-fedora (hotplug) $ oc get nncp -w
NAME STATUS REASON
hotplug-linux-bridge
hotplug-linux-bridge Progressing ConfigurationProgressing
hotplug-linux-bridge Progressing ConfigurationProgressing
...
hotplug-linux-bridge Available SuccessfullyConfigured

3. Run the command to add the new interface to the VM:
virtctl addinterface <vm-name> --network-attachment-definition-name <net-attach-def-name> --name <interface-name>
$ virtctl addinterface vm-fedora --network-attachment-definition-name hp-br-nad --name hp2

Actual results:
<BUG> The action succeeds, with no failure.
The new interface appears in the VMI spec:
$ oc get vmi vm-fedora -o yaml
...
interfaces:

• masquerade: {}
  name: default
• bridge: {}
  name: hp2
  ...
  networks:
• name: default
  pod: {}
• multus:
  networkName: hp-br-nad
  name: hp2

Expected results:
The action should fail with an error message.

Additional info: