[Failing Test]: PostCommit Nexmark Dataflow Runner v2 actually runs on Dataflow legacy runner

[Abacn]

What happened?

Workflow: https://github.com/apache/beam/actions/workflows/beam_PostCommit_Java_Nexmark_Dataflow_V2.yml

During release branch verification, after Dataflow v2 image rolled out (and before Dataflow Legacy runner image roll out), re-run PostCommit Nexmark Dataflow Runner v2 on #34794 still failing. The cause is the job trying to pull legacy worker container

"Error syncing pod, skipping" err="failed to \"StartContainer\" for \"java-streaming\" with ImagePullBackOff: \"Back-off pulling image \\\"gcr.io/cloud-dataflow/v1beta3/beam-java11-streaming:2.65.0\\\"\"" pod="default/df-main-runner-0502190529-45-05021205-syg8-harness-lps1" podUID="ceaf0ae17d44f5dc17e8566e8e09fc05"

and Dataflow UI indeed shows "Runner v2 Disabled"

Issue Failure

Failure: Test is continually failing

Issue Priority

Priority: 2 (backlog / disabled test but we think the product is healthy)

Issue Components

• Component: Python SDK
• Component: Java SDK
• Component: Go SDK
• Component: Typescript SDK
• Component: IO connector
• Component: Beam YAML
• Component: Beam examples
• Component: Beam playground
• Component: Beam katas
• Component: Website
• Component: Infrastructure
• Component: Spark Runner
• Component: Flink Runner
• Component: Samza Runner
• Component: Twister2 Runner
• Component: Hazelcast Jet Runner
• Component: Google Cloud Dataflow Runner