don't show 'take quiz' to teachers until they have published a quiz in ember

fixes CNVS-13222

test plan:
  - turn on fabulous quizzes
  - as a teacher
    - create a new quiz, but don't publish it
    - visit the quiz
    - click on the drop down menu
    - the take quiz option should not be present
    - publish the quiz
    - click on the drop down menu
    - the take quiz option should now be there

Change-Id: Ia29bde5b13a79dd1a9eaeead777eff9ced01aa00
Reviewed-on: https://gerrit.instructure.com/35548
Reviewed-by: Ahmad Amireh <ahmad@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>