Right now the "Reply-to" field is required when creating a new campaign. When the list has the "reply-to" field set it pulls from that value, and we're good to go.
But that's not always the case and sometimes that field is empty (reply-to isn't a required field when creating a list). Also, it's possible to send a campaign to a segment and that segment can filter subscribers from multiple lists, so those "From/Reply-to" are different.
In that case (empty reply-to field) it should just inherit the "From email" used on that campaign, simple and easy.
