fix drag/drop arrows not showing for IE10 on "Questions" tab

Fixes an issue where drag/drop arrows were not showing on the
"Questions" tab. For some reason, the "group_top" selector has been lost
in the original ERB markup, so due to some weird CSS selectors, the
icons didn't show up in IE10 only.

Test plan:
  - Visit the quiz edit page in all the browsers!
  - You should see the edit/trash/move icons when hovering over
    questions on the "Questions" tab.
  - You should not see those icons unless you are hovering.

fixes CNVS-11419

Change-Id: I97cfd634dd78a9021f0787c851452b46b47759f9
Reviewed-on: https://gerrit.instructure.com/31021
QA-Review: Myller de Araujo <myller@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Derek DeVries <ddevries@instructure.com>
Product-Review: Stanley Stuart <stanley@instructure.com>