[Release-1.5] Remove tasks referring to the deprecated tool (#6587)

* Also remove faq mentioned it

* Also in egress task

content/en/docs/tasks/traffic-management/egress/egress-gateway/index.md

@@ -745,11 +745,8 @@ external service.
 
 ## Troubleshooting
 
-1.  Check if you have [mutual TLS Authentication](/docs/tasks/security/authentication/authn-policy/) enabled in Istio.
-    If mutual TLS is enabled, make sure you create the configuration
-    items accordingly (note the remarks _If you have mutual TLS Authentication enabled in Istio, you must create..._).
-
-1.  If [mutual TLS Authentication](/docs/tasks/security/authentication/authn-policy/) is enabled, verify the correct certificate of the egress gateway:
+1.  If [mutual TLS Authentication](/docs/tasks/security/authentication/authn-policy/) is enabled, verify the correct certificate of the
+    egress gateway:
 
     {{< text bash >}}
     $ kubectl exec -i -n istio-system $(kubectl get pod -l istio=egressgateway -n istio-system -o jsonpath='{.items[0].metadata.name}')  -- cat /etc/certs/cert-chain.pem | openssl x509 -text -noout  | grep 'Subject Alternative Name' -A 1

content/en/faq/security/check-policy.md

@@ -1,14 +0,0 @@
----
-title: How can I check whether mutual TLS is enabled for a service?
-weight: 11
----
-
-The [`istioctl`](/docs/reference/commands/istioctl) command provides an option for this purpose. You can do:
-
-{{< text bash >}}
-$ istioctl authn tls-check $CLIENT_POD httpbin.default.svc.cluster.local
-HOST:PORT                                  STATUS     SERVER     CLIENT           AUTHN POLICY     DESTINATION RULE
-httpbin.default.svc.cluster.local:8000     OK         STRICT     ISTIO_MUTUAL     /default         istio-system/default
-{{< /text >}}
-
-Where `$CLIENT_POD` is the ID of one of the client service's pods.