add submission detail dialog to srgb

fixes CNVS-10137

test plan
=========
- navigate to screenreader gradebook
- select a student and an assignment
- click the submission details dialog
- verify that you can add comments and link to speedgrader for the
  current selected submission

Change-Id: Iea290c891c1476b200c5916fb829df74c329da71
Reviewed-on: https://gerrit.instructure.com/28766
Product-Review: Matthew Irish <mirish@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Matthew Irish <mirish@instructure.com>