Change the unit primitive for troubleshoot job

What does this MR do and why?

This adds the unit primitive for the /troubleshoot_job slash command tool.

Similar too: !157606 (merged)

Part of making this available to Enterprise Duo customers only. Issue: #457573 (closed)

ee/app/models/gitlab_subscriptions/features.rb

@@ -261,7 +261,6 @@ class Features
       suggested_reviewers
       subepics
       observability
-      tracing
       troubleshoot_job
       unique_project_download_limit
       vulnerability_finding_signatures