Makes the usage rights indicator more accessible

fixes CNVS-17221

Test Plan:
  - Enable Usage Rights
  - Go to New Files
  - Using a screenreader navigate to the usage rights
    column
  - It should read what the icon relays to a sighted user
    as well as the content that comes up in the tooltip

Change-Id: Iebe1d85a8f8fdf33effbd7df1e522f5965c9aa7b
Reviewed-on: https://gerrit.instructure.com/45349
Reviewed-by: Ryan Shaw <ryan@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Nathan Rogowski <nathan@instructure.com>
Product-Review: Clay Diffrient <cdiffrient@instructure.com>