Enable SupportTeamContributions outside of sandbox

What does this MR do and why?

Followup to !1985 (merged), dropping the sandbox parameter.

Expected impact & dry-runs

See https://gitlab.com/gitlab-org/quality/engineering-productivity/triage-ops-playground/-/merge_requests/7+ – opened by me, getting the label vs. https://gitlab.com/gitlab-org/quality/engineering-productivity/triage-ops-playground/-/merge_requests/8+ – opened by someone not from Support and not getting the label.

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