profile: allow changing avatar from course or group context

fixes CNVS-12335

test plan:
  * open your profile from within a course or group's People page
  * change your profile picture
  * verify that it is changed successfully

Change-Id: I53c93fbabe09a57801154cc6e4f9743c8945f1c3
Reviewed-on: https://gerrit.instructure.com/33259
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Joel Hough <joel@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Braden Anderson <banderson@instructure.com>