The tests of python3-repoze-who-plugins-sa are conflicting with tests of other packages.
As a quick fix, remove that folder. Long term, work with upstream to do either of following:
A. don't install the tests package
B. move the tests package into the repoze.who package
Pushed together with Python 2 removal.
This was open for F29, but I doubt anyone cares (or uses this on Python 3 anyway).
Please, reopen if this bites you on F29.