Adds h4 to student mastery individual outcome

Fixes: CNVS-14010

Test plan:
1) create a course with a learner
2) Add an outcome group  and an outcome
2) Navigate to the grades for a student, then the learning mastery tab
3) Expand the outcome group and see that the individual outcome title
   is in an h4.

Change-Id: I506ed259eb3064bad69c69e8b7505105a9167e16
Reviewed-on: https://gerrit.instructure.com/37461
Reviewed-by: Jayce Higgins <jhiggins@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: David Josse <david@instructure.com>
Product-Review: Matthew Wheeler <mwheeler@instructure.com>