Don't return duplicate ports from SRV query

[tpantelis]

If a service is defined with two ports with the same port number but different protocols, eg

Ports: []corev1.ServicePort{
    {
        Name:     "tcp",
        Port:     42,
        Protocol: corev1.ProtocolTCP,
    },
    {
        Name:     "udp",
        Port:     42,
        Protocol: corev1.ProtocolUDP,
    },
},

LH returns both records:

0 50 42 hello.mcs-conformance-1655466269.svc.clusterset.local
0 50 42 hello.mcs-conformance-1655466269.svc.clusterset.local

while a .svc.cluster.local query returns only one of them. LH should do the same.