linkerd: update prometheus URL based on the latest 2.10 changes

In Linkerd 2.10, The Prometheus instance moved into the `viz`
extension which is installed separately from the core
control-plane. This means that the prometheus now exists in
the `linkerd-viz` namespace by default unless overriden.

This PR updates the URl to reflect the same

Signed-off-by: Tarun Pothulapati <tarunpothulapati@outlook.com>

kustomize/linkerd/patch.yaml

@@ -11,7 +11,7 @@ spec:
             - -log-level=info
             - -include-label-prefix=app.kubernetes.io
             - -mesh-provider=linkerd
-            - -metrics-server=http://linkerd-prometheus:9090
+            - -metrics-server=http://linkerd-prometheus.linkerd-viz:9090
 ---
 apiVersion: rbac.authorization.k8s.io/v1beta1
 kind: ClusterRoleBinding