Making reject comment mandatory in Approve Purchase Orders Fiori app

Hello experts,

We have configured the standard Approve Purchase Orders app in our landscape. While approving/rejecting PO work items from the Fiori app we see a box for entering comments before approving/rejecting the work item.

Is there any configuration setting (like available for making comment mandatory in My Inbox app) using which we can make the comment mandatory while rejecting the items? Or it extending the app and making code changes the only way to achieve this?

Regards,

Saurabh