do not confirm navigation for auto-previewed content for QO
do not confirm navigation for auto-previewed content for QO

fixes QO-594
flag = none

test plan:
 - bring up canvas with canvas-rce-api and canvadocs-server
 - add a pdf file to the course (or a few files)
 - create a Classic Quiz
 - using the RCE, add a link to that pdf file (via Files tab)
   in either the quiz description or to any question
 - highlight the link and click the link icon in the toolbar
   to open the link settings modal
 - enable "auto open inline preview" and click "Update Link"
 - save the quiz and take it as a student
 - when the student loads the quiz, they should not see any
   alert/confirmation message saying 'You are about to
   navigate away from this page, continue anyway?'
 - if you actually are about to navigate away from the quiz
   (by clicking any other link), you should still get this
   confirmation alert
 - expanding/minimizing the preview should not show the alert
 - clicking the link itself (to download the pdf) will still
   show the alert

Change-Id: Ie32f719524ab87b966fdf4c1b13dc7d195c219f3
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/232545
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
QA-Review: Jim Simon <801be5e70e868c2755b908d78d4b55d1f02ffb8c@instructure.com>
Product-Review: Kevin Dougherty <d976013e3ceb631f24c072156980cd9ccba4cf84@instructure.com>
Reviewed-by: Alex Slaughter <11669a22a05ead38ed9badafd55ef4c5386724b6@instructure.com>

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