Converts wiki page title to use h1 rather than h2

fixes CNVS-14906

Test Plan:
  1. Navigate to a page under Pages in a course
  2. In VO, press ctrl+option+cmd+h to go to the first and
     only header
  3. Press a second time to confirm that there are no more
     headers
  4. Hold shift while pressing those same keys to confirm that
     there are no previous headers
  5. Header should be recognized as a H1

Change-Id: I29ee832829581f08e23f0d3b01a264e908c67deb
Reviewed-on: https://gerrit.instructure.com/40673
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Ryan Shaw <ryan@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Cosme Salazar <cosme@instructure.com>