Fix Vertex batch live tests

[aksg87]

Summary

• Supply the required Vertex batch caching and retention settings without changing shared-bucket lifecycle rules.
• Use the supported US multi-region in Vertex live tests and the batch guide; keep VERTEX_LOCATION overridable.
• Check the current schema_config argument passed to batch inference.
• Verify cache reuse with identical grounded extractions and no second batch submission, replacing timing checks and bucket-wide cache scans.

No runtime code or dependency changes.

Verification

• pytest tests --import-mode=importlib -q -m 'not live_api and not requires_pip and not integration': 838 passed against the installed release-candidate wheel.
• tox -e format,lint-src,lint-tests: passed.
• Non-batch live API suite: 12 passed.
• OpenAI Batch live test: passed with two synthetic documents; uploaded and output files cleaned up.
• Vertex batch extraction/cache live tests: 2 passed, including schema forwarding, grounded medication/dosage results, and cache reuse without another submission.

Live validation used fresh test buckets; test objects and buckets were cleaned up. The repository's shared bucket and its lifecycle policy were not modified.