## Summary
- Adds a new GitHub Actions workflow that sends a Slack alert when
Studio E2E tests or unit tests fail on master
- Uses `workflow_run` trigger so no changes needed to existing CI
workflows
- Reuses the existing `SLACK_DASHBOARD_WEBHOOK_URL` secret
Closes FE-2883
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## Summary by CodeRabbit
* **Chores**
* Implemented automated Slack notifications to alert when master branch
build failures occur, including build run details, commit information,
and commit author.
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