add 'location' in example parameter (Azure#24675)

Author: kazrael2119

specification/frontdoor/resource-manager/Microsoft.Network/stable/2022-05-01/examples/WafPolicyCreateOrUpdate.json

@@ -5,6 +5,7 @@
     "resourceGroupName": "rg1",
     "policyName": "Policy1",
     "parameters": {
+      "location": "WestUs",
       "properties": {
         "policySettings": {
           "enabledState": "Enabled",