Add resolve vulnerability handler

What does this merge request do and why?

This MR adds a facility to trigger resolve vulnerability for a given vulnerability report.

• Relates to #244 (closed)
• Work item #244 (closed)

How to set up and validate locally

1. Ensure GCP environment variables are setup.

2. Check out to this merge request's branch.

3. Execute a test run.

   poetry run promptlib etv eval --config-file data/config/resolve_vulnerability/eval_resolve_vulnerability_experiment.json --test-run --sample-size 1

Merge request checklist

• I've ran the affected pipeline(s) to validate that nothing is broken.
• Tests added for new functionality. If not, please raise an issue to follow up.
• Documentation added/updated, if needed.