Student profile CSV background task tech debt

TNL-525

These 4 commits address 4 fairly small instances of technical debt that @nasthagiri and I came across while working on the backgroundify student profile CSV story.

@jimabramson @nasthagiri please review.

@cahrens FYI
Is there a reason why `start_time` is passed in as a parameter rather than automatically setting it in this `__init__` method?