Fix Prometheus scraping for pod-identity-webhook

The Service annotation for the pod-identity-webhook is asking Prometheus
to scrape its metrics from `https://` but this results in a HTTP 404 Not
Found response.
The pod-identity-webhook pods expose their metrics via HTTP on TCP port
9999 (the same port where the healthz checks go).
Therefore update the annotations to use `http://:9999` instead.

tests/integration/update_cluster/irsa/data/aws_s3_object_minimal.example.com-addons-eks-pod-identity-webhook.addons.k8s.io-k8s-1.16_content

@@ -243,8 +243,8 @@ apiVersion: v1
 kind: Service
 metadata:
   annotations:
-    prometheus.io/port: "443"
-    prometheus.io/scheme: https
+    prometheus.io/port: "9999"
+    prometheus.io/scheme: http
     prometheus.io/scrape: "true"
   creationTimestamp: null
   labels:
@@ -269,8 +269,8 @@ data:
 kind: ConfigMap
 metadata:
   annotations:
-    prometheus.io/port: "443"
-    prometheus.io/scheme: https
+    prometheus.io/port: "9999"
+    prometheus.io/scheme: http
     prometheus.io/scrape: "true"
   creationTimestamp: null
   labels:

upup/models/cloudup/resources/addons/eks-pod-identity-webhook.addons.k8s.io/k8s-1.16.yaml.template

@@ -185,8 +185,8 @@ metadata:
   name: pod-identity-webhook
   namespace: kube-system
   annotations:
-    prometheus.io/port: "443"
-    prometheus.io/scheme: "https"
+    prometheus.io/port: "9999"
+    prometheus.io/scheme: "http"
     prometheus.io/scrape: "true"
 spec:
   ports:
@@ -202,8 +202,8 @@ metadata:
   name: pod-identity-webhook
   namespace: kube-system
   annotations:
-    prometheus.io/port: "443"
-    prometheus.io/scheme: "https"
+    prometheus.io/port: "9999"
+    prometheus.io/scheme: "http"
     prometheus.io/scrape: "true"
 data:
   config: {{ PodIdentityWebhookConfigMapData }}
@@ -217,4 +217,4 @@ spec:
   selector:
     matchLabels:
       app: pod-identity-webhook
-  maxUnavailable: 50%
+  maxUnavailable: 50%