create communication_channels on users shard
create communication_channels on users shard

also look for the communication channel on the users shard

test plan
 - have an account with a trust in place
 - have a user with a login on both accounts
 - on the account that is not on the same shard as the user
 - run a user import that adds an email to the sis_id of the login
 - it should be on the users shard

fixes VICE-889
flag=none

Change-Id: I1a4155892d519691d26797620a0d9a1b9c00d8e4
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/249192
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Matthew Lemon <7bd6faf60934a850234395b3b97cb1fc9250fa11@instructure.com>
QA-Review: Matthew Lemon <7bd6faf60934a850234395b3b97cb1fc9250fa11@instructure.com>
Product-Review: Matthew Lemon <7bd6faf60934a850234395b3b97cb1fc9250fa11@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms