Hide master broken trace in 'Click to expand' to reduce noise

What does this MR do and why?

This adds a Click to expand section around job traces in master broken incidents.

In incidents with large traces, I find myself annoyed by scrolling beyond the trace to reach the comment box under Investigation Steps.

For example, where I ended up making a new thread to communicate updates: gitlab-org/quality/engineering-productivity/master-broken-incidents#7028 (closed)

Expected impact & dry-runs

All new master broken incidents.

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