=per #15590 Increase efforts to in-order on start of AtLeastOnceDelivery

AtLeastOnceDelivery can delivery out-of-order, and that's OK.

Although, in the case of message replay followed by taking user land
commands which may trigger `deliver` calls, it is nicer to at least once
try to send the replayed but not confirmed deliveries *first*, before
sending the completely new deliveries.

Resolves #15590