updating placeholder version of prowImage with new 1.34 version

Author: drewhagen

releng/test_config.yaml

@@ -449,7 +449,7 @@ nodeK8sVersions:
   beta:
     args:
     - --repo=k8s.io/kubernetes=release-1.34
-    prowImage: gcr.io/k8s-staging-test-infra/kubekins-e2e:v20250807-xxxxxxxx-1.34 # TODO this is a placeholder, update with the actual image tag
+    prowImage: gcr.io/k8s-staging-test-infra/kubekins-e2e:v20250807-7b202b3ee9-1.34
   stable1:
     args:
     - --repo=k8s.io/kubernetes=release-1.33