Fix up the ora2 scores affected by the track changes bug.

  For affected assessments:
    - Sets PeerWorkflowItem.scored = 0 if currently = 1
    - Recalculates the score for the submission
    - If new score > old score, update the Score.points_earned with the new score
Did you run this wording by @jinpa already? I suspect we want to soften it as "may have been incorrectly graded" and I'm pretty sure we don't use the Oxford comma in our error texts.