fix mistakenly sending messages to old / deleted comm channels
fix mistakenly sending messages to old / deleted comm channels

fixes COMMS-1489

Test Plan
Without patchset
1. Create a user with a confirmed email addresses
2. Have them add a new email address and delete their old one
3. Use forget password with old address
4. See notifications go out for old address

With patchset notice that they do not go out to the old address

Change-Id: I35dcb69e6ec7e164dd8b7b302f04fbc9079a3d46
Reviewed-on: https://gerrit.instructure.com/168263
Tested-by: Jenkins
Reviewed-by: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
Reviewed-by: Landon Gilbert-Bland <60d9ff23682c863d36b48b4c32c5ce5f434d29c0@instructure.com>
QA-Review: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
Product-Review: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms