[Task]: Clean up Java Tests workflow

[damondouglas]

What needs to happen?

.github/workflows/java_tests.yml has an opportunity for cleanup. First, an Authenticate on GCP step that uses google-github-actions/auth@v1. Said step provides Google Cloud authentication using an outdated static credential pattern and can be removed. Notably the Java Word count Dataflow is skipped and could be removed since we have numerous other tests that cover this.

Issue Priority

Priority: 2 (default / most normal work should be filed as P2)