After kubeconfig was replaced with an in-cluster service account, k8sClient was returning null and thus no test summaries were being written to ConfigMaps. This change returns a default Kubeconfig for the k8sClient when one is not passed in an environment variable.
Write test result for each test to a K8s ConfigMap so it can be read by the workflow after the tests have completed. This replaces attempts to capture stdout/stderr which for some reason fails to show all test status.
