jsonnet: kube-prometheus adapt to changes to veth interfaces names

With OVN, the container veth network interface names that used to start
with `veth` has now changed to `<rand-hex>{15}@if<number>`(see Related
Links below).

This patch adapts to the new change introduced in ovn and ignores the network
interfaces that match `[a-z0-9]{15}@if\d+` in addition to those starting
with `veth`

Related Links:
  - https://github.com/openshift/ovn-kubernetes/blob/master/go-controller/vendor/github.com/containernetworking/plugins/pkg/ip/link_linux.go#L107
  - https://github.com/openshift/ovn-kubernetes/blob/master/go-controller/pkg/cni/helper_linux.go#L148



Signed-off-by: Sunil Thaha <sthaha@redhat.com>