Fix correct label

Signed-off-by: bmangoen <bmangoen@redhat.com>

Author: bmangoen

docs/migrate-from-sidecar-to-ambient/migration.adoc

@@ -462,7 +462,7 @@ Create the ZTunnel namespace and resource:
 kubectl get namespace ztunnel >/dev/null 2>&1 || kubectl create namespace ztunnel
 
 # If you are using discoverySelectors, label the namespace accordingly
-kubectl label namespace ztunnel istio.io/rev=default --overwrite
+kubectl label namespace ztunnel istio-discovery=enabled --overwrite
 
 # Wait for istiod to propagate the CA certificate ConfigMap to the ztunnel namespace
 kubectl wait --for=condition=Complete --timeout=120s job/wait-for-configmap -n ztunnel 2>/dev/null || \