redirect to login on submission show page
redirect to login on submission show page

fixes CNVS-3982

test plan
- log in as someone who can view a submission
- ensure that you can view the submission
- log out
- navigate to the submission's url
- ensure that you are directed to the login page and that
  no page error occurs

Change-Id: If52a572b0323f1adc5ec3e15338df437d3f28fb4
Reviewed-on: https://gerrit.instructure.com/18048
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Zach Pendleton <514dbb4d54d4f29e454990df7d075678f43f92aa@instructure.com>
QA-Review: Marc LeGendre <d33c80bc45d65303e33ca83108a9952b745af9ef@instructure.com>

loganrun/pincan,grahamb/canvas-lms,usmschuck/canvas,efrj/canvas-lms,HotChalk/canvas-lms,arrivu/jigsaw-lms,sli7246/canvas_branch,jay3126/canvas-lms,landonwilkins/canvas-lms,SwinburneOnline/canvas-lms,Unow/canvas-lms,arrivu/hoodemo,arrivu/hoodemo,landonwilkins/canvas-lms,kyroskoh/canvas-lms,efrj/canvas-lms,Rvor/canvas-lms,arrivu/hoodemo,SwinburneOnline/canvas-lms,skmezanul/canvas-lms,antoniuslin/canvas-lms,tgroshon/canvas-lms,sdeleon28/canvas-lms,va7map/canvas-lms,tgroshon/canvas-lms,leftplusrightllc/canvas-lms,wrdsb/canvas-lms,Rvor/canvas-lms,arrivu/arrivu-lms,usmschuck/canvas,arrivu/jigsaw-lms,sfu/canvas-lms,sfu/canvas-lms,merichar/canvas-lms,usmschuck/canvas,sli7246/canvas_branch,roxolan/canvas-lms,greyhwndz/canvas-lms,rup/Tarrax,arrivu/arrivu-lms,whalejasmine/canvas-lms,leftplusrightllc/canvas-lms,shidao-fm/canvas-lms,jay3126/canvas-lms,juoni/canvas-lms,leftplusrightllc/canvas-lms,arrivu/qibla-ecampus,loganrun/pincan,Unow/canvas-lms,utkarshx/canvas-lms,wrdsb/canvas-lms,usmschuck/canvas,Unow/canvas-lms,samuels410/greatlakes-lms,merichar/canvas-lms,wye0220/shindig-canvas,ShreniiNepal/shrenii_lmp,sli7246/canvas_branch,redconfetti/canvas-lms,fronteerio/canvas-lms,Unow/ins,sfu/canvas-lms,ShreniiNepal/shrenii_lmp,fronteerio/canvas-lms,Rvor/canvas-lms,Jyaasa/canvas-lms,skmezanul/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,arrivu/arrivu-lms,roxolan/canvas-lms,venturehive/canvas-lms,samuels410/greatlakes-lms,antoniuslin/canvas-lms,tgroshon/canvas-lms,rup/Tarrax,wimemx/Canvas,Jyaasa/canvas-lms,jay3126/canvas-lms,whalejasmine/canvas-lms,skmezanul/canvas-lms,redconfetti/canvas-lms,wrdsb/canvas-lms,rup/Tarrax,SwinburneOnline/canvas-lms,grahamb/canvas-lms,shidao-fm/canvas-lms,va7map/canvas-lms,kyroskoh/canvas-lms,utkarshx/canvas-lms,landonwilkins/canvas-lms,va7map/canvas-lms,leftplusrightllc/canvas-lms,roxolan/canvas-lms,shidao-fm/canvas-lms,Unow/ins,HotChalk/canvas-lms,wimemx/Canvas,skmezanul/canvas-lms,Unow/ins,va7map/canvas-lms,HotChalk/canvas-lms,efrj/canvas-lms,wimemx/Canvas,efrj/canvas-lms,wrdsb/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,ShreniiNepal/shrenii_lmp,whalejasmine/canvas-lms,venturehive/canvas-lms,arrivu/qibla-ecampus,sdeleon28/canvas-lms,redconfetti/canvas-lms,juoni/canvas-lms,jay3126/canvas-lms,greyhwndz/canvas-lms,venturehive/canvas-lms,Jyaasa/canvas-lms,kyroskoh/canvas-lms,grahamb/canvas-lms,fronteerio/canvas-lms,utkarshx/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,wye0220/shindig-canvas,grahamb/canvas-lms,tgroshon/canvas-lms,Rvor/canvas-lms,samuels410/greatlakes-lms,sdeleon28/canvas-lms,kyroskoh/canvas-lms,loganrun/pincan,ShreniiNepal/shrenii_lmp,roxolan/canvas-lms,samuels410/greatlakes-lms,merichar/canvas-lms,utkarshx/canvas-lms,Jyaasa/canvas-lms,fronteerio/canvas-lms,greyhwndz/canvas-lms,wye0220/shindig-canvas,SwinburneOnline/canvas-lms,juoni/canvas-lms,juoni/canvas-lms,whalejasmine/canvas-lms,redconfetti/canvas-lms,arrivu/qibla-ecampus,landonwilkins/canvas-lms,sdeleon28/canvas-lms,greyhwndz/canvas-lms,arrivu/jigsaw-lms,shidao-fm/canvas-lms,djbender/canvas-lms,antoniuslin/canvas-lms,antoniuslin/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms