disables annotations on graded discussion replies
disables annotations on graded discussion replies

fixes RD-4586

test plan:
- make sure your canvas is tied to canvadocs
- make sure your course discussions allow
   attachments to replies
- make sure you have a graded discussion assignment
- have 1 student reply once
- have another student reply multiple times, in
   and/or out of threads
- as a teacher, go to speedgrader for the
   graded discussion
- verify that for all students, each file
   attachment do not have annotation controls
   when viewed in canvadocs

demo video: http://take.ms/wnrWm

Change-Id: I4dfbd2fe5eb06e64e2657b6c364736a6582f975c
Reviewed-on: https://gerrit.instructure.com/139740
Tested-by: Jenkins
Reviewed-by: Daniel Lee <cf722ebef997381e7a050a89edd2d4ff7bce2601@instructure.com>
Product-Review: Caleb Guanzon <54fa1f30d451e4f3c341a8f3c47c9215fd0be9c6@instructure.com>
QA-Review: Caleb Guanzon <54fa1f30d451e4f3c341a8f3c47c9215fd0be9c6@instructure.com>

instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,djbender/canvas-lms