Add a failureDomain for multiple zone templates

There's a new field called "trafficDistribution" in k/k, whose e2e
test needs 3 zones.

feature: kubernetes/kubernetes#123487
e2e: kubernetes/kubernetes#123812

Signed-off-by: Zhecheng Li <zhechengli@microsoft.com>

tests/k8s-azure/manifest/cluster-api/linux-vmss-multiple-zones-ci-version.yaml

@@ -261,6 +261,7 @@ spec:
   failureDomains:
     - "1"
     - "2"
+    - "3"
   replicas: ${WORKER_MACHINE_COUNT}
   template:
     spec:
@@ -435,6 +436,7 @@ spec:
   failureDomains:
     - "1"
     - "2"
+    - "3"
   replicas: ${WINDOWS_WORKER_MACHINE_COUNT:-0}
   template:
     spec: