Add nodefaults to group edit form

[braders]

Overview

Add smarty:nodefaults to URLs in the group edit form.

Before

The links were broken in some environments (as previously noted on other PRs, this does not currently affect Drupal, due to differing URL strucutres between CMSs).

After

The links work.

[civibot]

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[eileenmcnaughton]

@braders thanks! Maybe we should remove the drupal by-passes that don't work on Wordpress?

[braders]

@eileenmcnaughton I have a fair few more problematic URLs lined up to open PRs for first, but once that's done I totally agree the bypass which only works in Drupal should go.

[eileenmcnaughton]

@braders yay!