launch help links in new window
launch help links in new window

fixes CNVS-31392

Test Plan:
- You need access to help menu navigation
  if you already have it set up ignore these steps
  - in Rails console paste
    Setting.set("show_feedback_link", "true")
  - restart server (if running locally)
- Go to the help menu on the left
- click on a help link
- notice it launches in new window

Change-Id: I02e4847207b4685308f83ce517fd210c70c6508c
Reviewed-on: https://gerrit.instructure.com/89146
Tested-by: Jenkins
Reviewed-by: Clay Diffrient <9dff2e5c98626d20d2848250c411e8009465bb87@instructure.com>
QA-Review: Heath Hales <8ca81b68c7e2592ac614bd07f22fcc735ca55f93@instructure.com>
Product-Review: Robert Lamb <bf934bf7cdbebe5899399a138c0cb75c4d783999@instructure.com>

matematikk-mooc/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,venturehive/canvas-lms,HotChalk/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,matematikk-mooc/canvas-lms,HotChalk/canvas-lms,matematikk-mooc/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,matematikk-mooc/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,HotChalk/canvas-lms,grahamb/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms