Add 30 sec delay before nudging for broken master labels

What does this MR do and why?

Describe in detail what your merge request does and why.

Expected impact & dry-runs

Adds a 30sec delay before nudging team member to apply master broken labels.

Re: gitlab-org/quality/engineering-productivity/master-broken-incidents#3821 (comment 1599880700)

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