set task_queue to NA when it is not there in the task
set task_queue to NA when it is not there in the task

specifically happening for send_unknown_user_type_stats tasks where intermittently task_queue is not set for the task

dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq