Disabling aad auth for legal service

As Istio AuthN got enabled in R2 services,Disabling AAD authentication using Istio auth property. Added Istio auth Env variable and set to true in helm charts template

devops/azure/chart/templates/deployment.yaml

@@ -118,3 +118,5 @@ spec:
             value: http://entitlements-azure/entitlements/v1
           - name: entitlements_service_api_key
             value: "OBSOLETE"
+          - name: azure_istioauth_enabled
+            value: "true"