test plan:
* should be able to mark the checkbox when creating
a global announcement for an account (other than site
admin) to queue a job to send the announcement in
a notification to all applicable users
closes #CORE-3384
Change-Id: I0540196164be283f3acc6c6b5232a945e1916fbe
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/212448
Tested-by: Jenkins
Product-Review: Lauren Williams <lcwilliams@instructure.com>
Reviewed-by: Mysti Lilla <mysti@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Jeremy Putnam <jeremyp@instructure.com>