R1:87f878ec8a77

Stop trying to CC merchants on invoices/receipts

Summary:
Fixes T13341. Currently, cart emails (invoices/receipts) are sent to members of the associated merchant account. This was just a simple way to keep an eye on things when this was first written.

The system works fine, and recent changes (almost certainly D20525) stopped these emails from working (presumably because of the slightly weird merchant permissions model).

This could be sorted out in more detail, but it looks like the path forward is to…