Conflict between defaults.order and collection.order configs

[guilliamxavier]

API Platform version(s) affected: 2.6.3

Description
The defaults.order config value, which would work as the global equivalent of https://api-platform.com/docs/core/default-order/#overriding-default-order (fields array), is also used in place of collection.order (direction string), which causes a TypeError.

How to reproduce
Config:

api_platform:
    defaults:
        order: [createdAt, id]

Error (on collection GET request):

Argument 1 passed to ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\OrderExtension::__construct() must be of the type string or null, array given

Possible Solution
Revert the order-related changes of dc461fc (note that, unlike the collection.pagination.* non-*_parameter_name keys, collection.order is not deprecated, so I don't see the reason for wanting to move it to defaults.order, even more so since that key was already used after #3151)

Additional Context
Workaround for now: use the explicit attributes sublevel:

api_platform:
    defaults:
        attributes:
            order: [createdAt, id]