CLC-4458 - Updated #load_new_active_users to only initialize array of new active users if none returned from #new_active_user_uids
CLC-4458 - Updated Canvas::AddNewUsers#sync_new_active_users so that it does not attempt to import an empty new user set
Merge pull request #3117 from redconfetti/QA-CLC-4458-fix-empty-user-set

[QA] CLC-4458 - sync-canvas-new-users.sh reported ORA-00936: missing expression