Fix breadcrumb style broken in external_file page

What does this MR do and why?

Fix breadcrumb style broken in external_file page

Changelog: fixed

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Before	After

How to set up and validate locally

1. Start GDK
2. Run locally FILTER=14_pipelines NEW_PROJECT=1 bundle exec rake db:seed_fu. If this runs successfully, you should see a success message like Successfully seeded 'r-analytics-group-1710898305/r-analytics-project-1710898305'.
3. Go to /-/pipelines of the new project.
4. For any of the pipelines, visit the build:linux job of the build stage.
5. Click Browser Artifacts.
6. Click ci_artifacts.txt.