This is part of a removal of the many override methods of toggle
flag/namespace classes. This allows us to remove imports of test modules
from production code.
This doesn't handle the default case where the showanswer has never
been touched, in which case it will continue to return Finished,
but that also happens when it's turned off so this just helps out
for all of the other cases.
We noticed that since users can choose to reset their due dates,
they would have the ability to let due dates pass and then for any
assessment that allows viewing the answer after the due date would be
visible. The user could thus view all answers and then reset their
due dates to receive a perfect score.
This PR works to fix that issue by changing all show answer values
to not take into account being past the due date when inside a PLS
course.
