add a preview quiz button to ember quizzes page

Test plan:
  - As a teacher, you should be able to preview a quiz on fabulous
    quizzes.

closes CNVS-12442

Change-Id: Iec3aa3735b47e4b71d3a92d7f0b479bc3bd3c475
Reviewed-on: https://gerrit.instructure.com/35206
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Derek DeVries <ddevries@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Stanley Stuart <stanley@instructure.com>