Detect gl-support-bot as an automation account

What does this MR do and why?

This will avoid wrong community-authored issue detection such as gitlab-org/gitlab#411009 (comment 1387708390).

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