OSDOCS-5158 adding admonition about storage known issue

Author: bscott-rh

modules/installation-gcp-enabling-confidential-vms.adoc

@@ -18,6 +18,11 @@ You can use Confidential VMs when installing your cluster. Confidential VMs encr
 :FeatureName: Confidential Computing
 include::snippets/technology-preview.adoc[]
 
+[IMPORTANT]
+====
+Due to a known issue, you cannot use persistent volume storage on a cluster with Confidential VMs. For more information, see link:https://issues.redhat.com/browse/OCPBUGS-7582[OCPBUGS-7582].
+====
+
 .Prerequisites
 * You have created an `install-config.yaml` file.