show roles for cross shard users

test plan
 - do an lti launch
 - roles should show up for cross shard users
 - the following substitutions should still work
   * $Canvas.user.id
   * $Canvas.user.sisSourceId
   * $Canvas.user.loginId
   * $Canvas.enrollment.enrollmentState
   * $Canvas.membership.concludedRoles
   * $Canvas.membership.roles

fixes PLAT-648

Change-Id: Ic4c3639a95b4528628f8dd2d205cd8250c1b7d11
Reviewed-on: https://gerrit.instructure.com/41214
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Nathan Mills <nathanm@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Brad Humphrey <brad@instructure.com>