Update action-groups.md

clarify tst action group process

Author: jacegummersall

articles/azure-monitor/alerts/action-groups.md

@@ -110,7 +110,7 @@ When you create or update an action group in the Azure portal, you can test the
 1. [Create an action group in the Azure portal](#create-an-action-group-in-the-azure-portal). 
 
    > [!NOTE]
-   > If you're editing an existing action group, save the changes to the action group before testing.
+   > The action group must be created and saved before testing. If you're editing an existing action group, save the changes to the action group before testing.
 
 1. On the action group page, select **Test action group**.