exclude kube-system from kyverno policies

reports are being shown for policies against resources in kube-system - determine whether this is intended behaviour as nothing appears to be being blocked despite the policies configured in enforcement mode.

$ kubectl get policyreports.wgpolicyk8s.io -A | head -10
NAMESPACE       NAME                                   KIND          NAME                                                        PASS   FAIL   WARN   ERROR   SKIP   AGE
kube-system     003f135c-0587-400f-be33-6f7d26bb336b   Pod           cern-magnum-falco-kt7k9                                     9      3      0      0       0      147m
kube-system     08bcefa9-59f9-4ac9-8caf-8070cf498ee7   ReplicaSet    hubble-ui-689b9b484d                                        12     0      0      0       0      147m
kube-system     1188d843-85b6-4ce3-a23e-eb9ac25f98fd   Pod           cern-magnum-node-problem-detector-f8jxs                     10     2      0      0       0      147m
kube-system     15bc9707-4f0a-4108-b83d-c047a81e6b8b   Pod           cern-magnum-eosxd-csi-nodeplugin-gms4k                      8      4      0      0       0      147m
kube-system     18f81a20-8ea9-4bd5-bdbd-f9004a40108e   Deployment    cern-magnum-node-feature-discovery-gc                       12     0      0      0       0      147m
kube-system     1aeaebc4-52b4-48d4-b8da-fab2b8199ac9   Pod           hubble-relay-86dd489d4c-tx5gz                               12     0      0      0       0      147m
kube-system     2539e7be-9a92-4f89-b921-405bef67b712   DaemonSet     cern-magnum-node-problem-detector                           10     2      0      0       0      147m
kube-system     25d79177-479d-433e-b9a6-6b536f4058e5   Pod           openstack-cloud-controller-manager-6xdj5                    10     2      0      0       0      147m
kube-system     26815bc1-ada7-4975-a8c3-54b53ab1b5e1   ReplicaSet    cern-magnum-coredns-autoscaler-6589977b54                   12     0      0      0       0      147m