Refactor, adjust applicable condition related to growth team refinement

What does this MR do and why?

Closes #1289 (closed)

1. Refactor the analyze_reactions method in growth_refine_automation_helper to split responsibilities into smaller methods.

2. Adjust the applicable conditions in add_thread_on_refinement processor to allow reacting to existing growth issues.

Expected impact & dry-runs

Dry run for scheduled: https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/3984204971

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