Multus failed to destroy network for pod: "failed to open netns %!q(<nil>): unknown FS magic on /var/run/netns/" on RHOCP 4

Issue

• Pods are stuck in "Terminating" state.

• The kubelet reports multus failing to remove the pod network:

  failed to destroy network for pod sandbox k8s_<pod_name>_<pod_namespace>_<pod_id>_0(<snadbox_id>): error removing pod <pod_namespace>_<pod_name> from CNI network \"multus-cni-network\": plugin type=\"multus\" name=\"multus-cni-network\" failed (delete): Multus: failed to open netns %!q(<nil>): unknown FS magic on \"/var/run/netns/<NETNAMESPACE_ID>\": 1021994"