[Bug] Allow both Order and OrderItem checker exist in the same promotion.

Hi community

At the moment, we pass both `Order` and `OrderItem` to `PromotionEligibilityChecker` to check it against the rules (see [here](https://github.com/Sylius/Sylius/blob/d5d9431790c340f5e9213ec01abb1e7c86fd60eb/src/Sylius/Bundle/CoreBundle/EventListener/OrderPromotionListener.php#L90-L96)). Also, all checkers are returning `false` if it doesn't support the type.

This means promotion cannot have rules that check Order and OrderItem at the same time. For example:

> Order Address Checker ("Order is shipping to US") + 
Item Category Checker ("Product is belongs to XX category")

This PR aim to fix this problem by ignoring all unsupported rules in `PromotionEligibilityChecker`. Please provide some feedback.

/cc @stloyd @umpirsky @pjedrzejewski
Updated.