A reply by a given blog at a given timestamp is the same reply
across the original post and every reblog of it. Drop PostID from
the UpdateNoteReplyText WHERE clause so a single API hit fills in
the replyText on every matching row at once.
Pair that with a per-iteration requery (limit 1) of the work list
so posts whose replies were already filled in as a side-effect of
a previous post's update are skipped without burning an API call.