fix(serializer): read groups off the root operation

[soyuka]

Q	A
Branch?	2.7
Tickets	n/a
License	MIT
Doc PR	n/a

#[ApiResource(
    provider: [RelationGroupImpactOnCollection::class, 'getData'],
    operations: [
        new GetCollection(),
        new Get(normalizationContext: ['groups' => 'related']),
    ]
)]

When using this declaration, we expect the groups to be active only on the Get operation but right now they're also active on the GetCollection.