e2e-test-config.sh configures the kafka admin endpoint template to http

Why:
On a kas-installer OSD cluster the e2e tests were failing with the config generated by
this script because there was no https route to the admin service.

e2e-test-config.sh

@@ -92,6 +92,7 @@ cat <<EOF
   "OPENSHIFT_IDENTITY_LOGIN_FORM_ID": "${REDHAT_SSO_LOGIN_FORM_ID}",
 
   "KAFKA_INSECURE_TLS": "true",
+  "KAFKA_INSTANCE_API_TEMPLATE": "http://admin-server-%s",
 
   "OPENSHIFT_API_URI": "https://$(${OC} get route kas-fleet-manager -n kas-fleet-manager-${USER} --template='{{ .spec.host }}')"
 }