Grant project permissions does not display vetos when canceled

Problem Definition

When vetoing the grant of project permissions ProjectPermissionGrantRequestedEvent, the veto message provided by the app is not displayed in the UI. Instead, all the UI shows is "Permission modification canceled", with no details on why.

Suggested Solution

The UI should display the veto messages provided when the request was canceled. (Additionally, it would be ideal if the veto messages could be formatted; see BSERV-4428 and BSERV-10910)

Why this is important

This allows app developers the ability to display context-rich responses/reasoning behind vetoing/canceling of project permission modifications.

Workaround

No workaround available