Stop posting explanation when adding labels

What does this MR do and why?

This MR stops posting explanations when adding labels.

Expected impact & dry-runs

The goal is to make automations less overwhelming and more actionable for users.

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

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This description was generated for revision 668ac292 using AI