Don't add unnecessary information on other users' profile pages

fixes CNVS-15446

test plan:
 - Turn on user profiles and avatars for an account.
 - Enroll a teacher and student in a course in that account.
 - As the student, go to the course's people page and find the
   teacher.
 - Click on the teacher to go to the teacher's profile page.
 - Check the page source as described by the jira issue.
 - Go to the student's own profile page.
 - The student should still be able to edit their own avatar.
 - The gravatar pane of the avatar edit dialog should be
   properly initialized with the student's default email
   address.

Change-Id: Iae4fa9d74161192eedda14316029ae8631570cfc
Reviewed-on: https://gerrit.instructure.com/40988
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>