Use Fake / More integration for integration unit tests

[mimowo]

What would you like to be cleaned:

We have the following unit tests recently added in , like this:

kueue/pkg/controller/jobs/statefulset/statefulset_webhook_test.go

Lines 402 to 419 in 8e63a6e

	"change in replicas (scale up with AppWrapper ownerReference while the previous scaling operation is still in progress)": {
	integrations: []string{appwrapper.FrameworkName},
	oldObj: testingstatefulset.MakeStatefulSet("test-sts", "test-ns").
	Queue("test-queue").
	Replicas(0).
	StatusReplicas(3).
	Obj(),
	newObj: testingstatefulset.MakeStatefulSet("test-sts", "test-ns").
	WithOwnerReference(metav1.OwnerReference{
	APIVersion: awv1beta2.GroupVersion.String(),
	Kind: "AppWrapper",
	Controller: ptr.To(true),
	}).
	Queue("test-queue").
	Replicas(3).
	StatusReplicas(1).
	Obj(),
	},

.

In this test we want to check the behavior when the CRD is owned by another CRD managed by Kueue.

For now we used AppWrapper as the owner integration, but it would be better to use a fake one.

Why is this needed:

The use of AppWrapper integration in the unit tests is not ideal, because:

• it makes unnecessary coupling between the integrations to AppWrapper
• the tests could not be cherry-picked to 0.10

[mimowo]

/cc @mbobrovskyi