fix: allow parameter provider as object

[deguif]

Q	A
Branch?	3.x
Tickets
License	MIT
Doc PR	api-platform/docs#...

The type-hint on ApiPlatform\Metadata\Parameter suggest a ParameterProviderInterface can be passed to provider property, but this won't work as expected in this case. This PR ensures it works.

Example:

#[Api\ApiResource(
    operations: [
        new Api\GetCollection(
            parameters: [
                'foo' => new Api\QueryParameter(
                    provider: new FooParameterProvider(),
                ),
            ],
        ),
    ]
)]
class Resource
{
}