Fix DatacenterID immutability test

The test was failing because it didn't refresh the object from the server
before attempting to update it. The CEL validation rule needs to compare
self with oldSelf, which requires the object to be fetched first to have
the correct resource version and state.

Add Get call before Update to ensure the validation rule can properly
check immutability.

Author: schegi

api/v1alpha1/ionoscloudmachine_types_test.go

@@ -134,6 +134,8 @@ var _ = Describe("IonosCloudMachine Tests", func() {
 				m := defaultMachine()
 				Expect(k8sClient.Create(context.Background(), m)).To(Succeed())
 				Expect(m.Spec.DatacenterID).To(Equal(defaultMachine().Spec.DatacenterID))
+				// Get the object from the server to ensure we have the latest version
+				Expect(k8sClient.Get(context.Background(), client.ObjectKey{Name: m.Name, Namespace: m.Namespace}, m)).To(Succeed())
 				m.Spec.DatacenterID = "6ded8c5f-8df2-46ef-b4ce-61833daf0961"
 				Expect(k8sClient.Update(context.Background(), m)).ToNot(Succeed())
 			})