multi_stage: add credential-only cluster profile test case

Add a test case for the scenario where cluster_profile is set without
any releases or tag_specification configured, verifying that no release
dependencies are required. This covers the credential-only use case
(e.g., Azure cleanup jobs using profile just for cloud credentials).

Author: raelga

pkg/steps/multi_stage/multi_stage_test.go

@@ -57,6 +57,12 @@ func TestRequires(t *testing.T) {
 		req: []api.StepLink{
 			api.ReleaseImagesLink(api.LatestReleaseName),
 		},
+	}, {
+		name: "cluster profile only without releases should not require any release links",
+		steps: api.MultiStageTestConfigurationLiteral{
+			ClusterProfile: api.ClusterProfileAWS,
+		},
+		req: nil,
 	}, {
 		name: "cluster profile with tag_specification should require release payload",
 		config: api.ReleaseBuildConfiguration{