Remove alpha1 Runs Client setup in init test

This commit removes the alpha1 Runs client setup in init_test
because the v1alpha1 Run support has been removed according to
TEP-114. The error occurs during e2e tests that is introduced as
a flake:
ie. https://storage.googleapis.com/tekton-prow/pr-logs/pull/tektoncd_pipeline/6567/pull-tekton-pipeline-alpha-integration-tests/1649045464097492992/build-log.txt

test/clients.go

@@ -62,7 +62,6 @@ type clients struct {
 	V1beta1TaskRunClient             v1beta1.TaskRunInterface
 	V1beta1PipelineRunClient         v1beta1.PipelineRunInterface
 	V1beta1CustomRunClient           v1beta1.CustomRunInterface
-	V1alpha1RunClient                v1alpha1.RunInterface
 	V1alpha1ResolutionRequestclient  resolutionv1alpha1.ResolutionRequestInterface
 	V1alpha1VerificationPolicyClient v1alpha1.VerificationPolicyInterface
 	V1PipelineClient                 v1.PipelineInterface

test/init_test.go

@@ -291,15 +291,6 @@ func getCRDYaml(ctx context.Context, cs *clients, ns string) ([]byte, error) {
 		printOrAdd(i)
 	}
 
-	v1alpha1Runs, err := cs.V1alpha1RunClient.List(ctx, metav1.ListOptions{})
-	if err != nil {
-		return nil, fmt.Errorf("could not get v1alpha1 runs: %w", err)
-	}
-	for _, i := range v1alpha1Runs.Items {
-		i.SetManagedFields(nil)
-		printOrAdd(i)
-	}
-
 	v1beta1CustomRuns, err := cs.V1beta1CustomRunClient.List(ctx, metav1.ListOptions{})
 	if err != nil {
 		return nil, fmt.Errorf("could not get v1beta1 customruns: %w", err)