[SPARK-49590] Fix javaVersion to jdkVersion in E2E spark-versions test template

### What changes were proposed in this pull request?

This PR corrects an invalid spec in e2e test template - `javaVersion` -> `jdkVersion` .

https://github.com/apache/spark-kubernetes-operator/blob/bc422fd4524f8139e934123cfe78d1833009026c/spark-operator-api/src/main/java/org/apache/spark/k8s/operator/spec/RuntimeVersions.java#L39

### Why are the changes needed?

The invalid test template causes e2e to fail e.g. https://github.com/apache/spark-kubernetes-operator/actions/runs/10745816799/job/29942467715?pr=118

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

CIs

### Was this patch authored or co-authored using generative AI tooling?

No

Closes #119 from jiangzho/test_file.

Authored-by: zhou-jiang <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: jiangzho

tests/e2e/spark-versions/spark-example.yaml

@@ -31,4 +31,4 @@ spec:
     spark.kubernetes.authenticate.driver.serviceAccountName: "spark"
   runtimeVersions:
     sparkVersion: ($V_SPARK_VERSION)
-    javaVersion: ($V_JAVA_VERSION)
+    jdkVersion: ($V_JAVA_VERSION)