add note to PS

Author: JnHs

articles/azure-arc/kubernetes/cluster-connect.md

@@ -77,6 +77,9 @@ A conceptual overview of this feature is available in [Cluster connect - Azure A
   |`*.servicebus.windows.net` | 443 |
   |`guestnotificationservice.azure.com`, `*.guestnotificationservice.azure.com` | 443 |
 
+> [!NOTE]
+> To translate the `*.servicebus.windows.net` wildcard into specific endpoints, use the command `\GET https://guestnotificationservice.azure.com/urls/allowlist?api-version=2020-01-01&location=<location>`. Within this command, the region must be specified for the `<location>` placeholder.
+
 - Replace the placeholders and run the below command to set the environment variables used in this document:
 
   ```azurepowershell