help: prompt for email address when user is not logged in

fixes CNVS-12002

test plan:
  * enable /plugins/error_reporting
  * open the login page
  * click "Help"
  * click "Report a Problem"
  * verify that there is a field for email address
  * log in
  * click "Help"
  * click "Report a Problem"
  * verify that there is no field for email address

Change-Id: I8ef05bd7e927de25716a3b5b9bc8f8844ed4d74f
Reviewed-on: https://gerrit.instructure.com/32375
Reviewed-by: Jon Willesen <jonw@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Braden Anderson <banderson@instructure.com>