Merge pull request #4913 from k8s-infra-cherrypick-robot/cherry-pick-4910-to-release-1.15

[release-1.15] use default k8s version for spot e2e test

Author: k8s-ci-robot

test/e2e/azure_test.go

@@ -433,7 +433,6 @@ var _ = Describe("Workload cluster creation", func() {
 				withFlavor("spot"),
 				withNamespace(namespace.Name),
 				withClusterName(clusterName),
-				withKubernetesVersion(e2eConfig.GetVariable(FlatcarKubernetesVersion)),
 				withControlPlaneMachineCount(1),
 				withWorkerMachineCount(1),
 				withControlPlaneWaiters(clusterctl.ControlPlaneWaiters{