CA policy - Do not ask to refine blocked issues

What does this MR do and why?

Describe in detail what your merge request does and why.

Update the refinement triage policy for Composition Analysis to ignore issue that have the blocked label.

This prevents asking to refine blocked issue that awaits further details.

Expected impact & dry-runs

Dry-run: https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/5331947593

No undesired side-effect observed.

These are strongly recommended to assist reviewers and reduce the time to merge your change.

See https://gitlab.com/gitlab-org/quality/triage-ops/-/tree/master/doc/scheduled#testing-policies-with-a-dry-run on how to perform dry-runs for new policies.

See https://gitlab.com/gitlab-org/quality/triage-ops/-/blob/master/doc/reactive/best_practices.md#use-the-sandbox-to-test-new-processors on how to make sure a new processor can be tested.

Action items

• If adding environment variables for reactive processors, update config/triage-web.yaml and .gitlab/ci/triage-web.yml
• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review