New toml config is not documented in Enabling Notifications for User Operations doc

The doc for. Enabling Notifications for User Operations https://is.docs.wso2.com/en/latest/learn/enabling-notifications-for-user-operations/#enabling-notifications-for-user-operations has old config model for using identity-event.properties file.

Need to modify nex gen doc also https://is.docs.wso2.com/en/5.11.0/learn/enabling-notifications-for-user-operations/
