Lost "View on Site" button with change to course.absolute_url

[ssciolla]

Thank you for contributing to this project!

• Make sure to search the issues for duplicates first!

Expected behavior (A clear and concise description of what you expected to happen) :

The admin page used to have a "View on Site" button, which is automatically generated when a model has a get_absolute_url method.

Describe the bug (Tell us what happens instead of the expected behavior) :

It looks like in PR #915 when we changed to using a property (i.e. course.absolute_url), we lost this button, meaning a link is no longer available from the edit page, only from the course list.

Screenshots/Video (If possible, add media to help explain your problem) :

The course referenced above is fabricated.

Additional context (Add any other context about the problem here) :

I think we can keep the property implementation and just add back a get_absolute_url method that uses the property. Something like this:

def get_absolute_url(self):
   return self.absolute_url

[jennlove-um]

Testing passes: The button displays and works as expected.