Set `Order.ReducedInventoryAfterPlacingTime` in advance

[gdlcf88]

Currently, after an order is created, the OrderCreatedEventHandler try to reduce inventory. If it succeeds, the ProductInventoryReductionEventHandler will set Order.ReducedInventoryAfterPlacingTime later.

I want less procedure. If an order contains no OrderLine with InventoryStrategy.ReduceAfterPlacing, the Order.ReducedInventoryAfterPlacingTime should be set directly during the order entity creation, and the ProductInventoryReductionAfterOrderPlacedResultEto will never publish.

This change improves the user experience, especially for the flash sales participants.

That will bring a breaking change.