Fix minor nits on the security tasks page Plugin CA Certificate (#12709)

* Fix minor nits on the security tasks page Plugin CA Certificate

Partially fixes: #12695

* Fix minor  nits on the security tasks page for certificate management

content/en/docs/tasks/security/cert-management/plugin-ca-cert/index.md

@@ -39,7 +39,7 @@ security protection.
 {{< /warning >}}
 
 {{< warning >}}
-Support for SHA-1 signatures is [disabled by default in Go 1.18](https://github.com/golang/go/issues/41682). If you are generating the certificate on macOS make sure you are using OpenSSL [as described in GitHub issue 38049](https://github.com/istio/istio/issues/38049).
+Support for SHA-1 signatures is [disabled by default in Go 1.18](https://github.com/golang/go/issues/41682). If you are generating the certificate on macOS make sure you are using OpenSSL as described in [GitHub issue 38049](https://github.com/istio/istio/issues/38049).
 {{< /warning >}}
 
 1.  In the top-level directory of the Istio installation package, create a directory to hold certificates and keys:
@@ -188,11 +188,33 @@ openssl command is expected.
     $ rm -rf certs
     {{< /text >}}
 
-*   Remove the secret `cacerts`, and the `foo` and `istio-system` namespaces:
+*   Remove the secret `cacerts`:
 
     {{< text bash >}}
     $ kubectl delete secret cacerts -n istio-system
-    $ kubectl delete ns foo istio-system
     {{< /text >}}
 
-*   To remove the Istio components: follow the [uninstall instructions](/docs/setup/getting-started/#uninstall) to remove.
+*   Remove the authentication policy from the `foo` namespace:
+
+    {{< text bash >}}
+    $ kubectl delete peerauthentication -n foo default
+    {{< /text >}}
+
+*   Remove the sample applications `sleep` and `httpbin`:
+
+    {{< text bash >}}
+    $ kubectl delete -f samples/sleep/sleep.yaml -n foo
+    $ kubectl delete -f samples/httpbin/httpbin.yaml -n foo
+    {{< /text >}}
+
+*   Uninstall Istio from the cluster:
+
+    {{< text bash >}}
+    $ istioctl uninstall --purge -y
+    {{< /text >}}
+
+*   Remove the namespace `foo` and `istio-system` from the cluster:
+
+    {{< text bash >}}
+    $ kubectl delete ns foo istio-system
+    {{< /text >}}

content/en/docs/tasks/security/cert-management/plugin-ca-cert/snips.sh

@@ -111,5 +111,21 @@ rm -rf certs
 
 snip_cleanup_2() {
 kubectl delete secret cacerts -n istio-system
+}
+
+snip_cleanup_3() {
+kubectl delete peerauthentication -n foo default
+}
+
+snip_cleanup_4() {
+kubectl delete -f samples/sleep/sleep.yaml -n foo
+kubectl delete -f samples/httpbin/httpbin.yaml -n foo
+}
+
+snip_cleanup_5() {
+istioctl uninstall --purge -y
+}
+
+snip_cleanup_6() {
 kubectl delete ns foo istio-system
 }

content/en/docs/tasks/security/cert-management/plugin-ca-cert/test.sh

@@ -60,6 +60,7 @@ _verify_same snip_verifying_the_certificates_5 "$snip_verifying_the_certificates
 # @cleanup
 snip_cleanup_1
 snip_cleanup_2
-#TODO fix cleanup instructions in doc and then remove the following 2 lines
-kubectl get validatingwebhookconfigurations -o custom-columns=NAME:.metadata.name --no-headers | xargs kubectl delete validatingwebhookconfigurations
-kubectl get mutatingwebhookconfigurations -o custom-columns=NAME:.metadata.name --no-headers | xargs kubectl delete mutatingwebhookconfigurations
+snip_cleanup_3
+snip_cleanup_4
+snip_cleanup_5
+snip_cleanup_6