ember quiz stats tab does not add browser history

closes CNVS-12825

test plan:
  - emable fabulous quizzes
    - as an instructor navigate to quiz show
    - click on several tabs including Statistics
    - click browser back button
      - verify that you are on previous page (not previous tab)

Change-Id: I44a046a526aa8decf9e49b1118ab970fbc7d1a1f
Reviewed-on: https://gerrit.instructure.com/34238
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Reviewed-by: Derek DeVries <ddevries@instructure.com>
Product-Review: Jason Madsen <jmadsen@instructure.com>