always show gb2 "move total column" option

fixes CNVS-15081

Test plan:
  make sure you can move your total column in gb2 whether or not your
  assignment groups are weighted.

Change-Id: I7e76f1ea95f67de326ba77fbf963017bb824a881
Reviewed-on: https://gerrit.instructure.com/39984
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
QA-Review: Amber Taniuchi <amber@instructure.com>
Product-Review: Cameron Matheson <cameron@instructure.com>