outcome results: persist tab selection to URL

fixes CNVS-10608

test plan:
  * open gradebook
  * select the learning mastery view
  * verify that you can switch views with your browser's
    back and forward buttons
  * refresh the page
  * verify that you are on the same view

Change-Id: Ia3657f7113cd9473ec9b3583d123eaf59c03d70f
Reviewed-on: https://gerrit.instructure.com/28845
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Willesen <jonw@instructure.com>
QA-Review: Steven Shepherd <sshepherd@instructure.com>
Product-Review: Braden Anderson <banderson@instructure.com>