[Bug] Fix k8s test bug (#3997)

Co-authored-by: gaoyan1998 <gaoyan1998@users.noreply.github.com>

Author: gaoyan1998

dinky-gateway/src/main/java/org/dinky/gateway/kubernetes/KubernetesGateway.java

@@ -87,10 +87,14 @@ public void init() {
     protected void initConfig() {
         flinkConfigPath = config.getClusterConfig().getFlinkConfigPath();
         flinkConfig = config.getFlinkConfig();
-        if (!isValidTaskName(flinkConfig.getJobName())) {
-            throw new GatewayException(
-                    "In Kubernetes mode, task names must start and end with a lowercase letter or a digit, "
-                            + "and can contain lowercase letters, digits, dots, and hyphens in between.");
+        String jobName = flinkConfig.getJobName();
+        if (TextUtil.isEmpty(jobName)) {
+            jobName = this.configuration.getString(KubernetesConfigOptions.CLUSTER_ID.key(), null);
+        }
+        if (!isValidTaskName(jobName)) {
+            throw new GatewayException(jobName
+                    + " is not Valid. In Kubernetes mode, task names must start and end with a lowercase letter or a digit, "
+                    + "and can contain lowercase letters, digits, dots, and hyphens in between.");
         }
         k8sConfig = config.getKubernetesConfig();