Stop failing on stale browser console allowlist specs

What does this MR do and why?

The browser console allowlist validator no longer fails when a specs path matches no file. It still requires each entry to list at least one spec.

The existence check could break master. On 2026-10-13, MR 260064 deleted a feature spec that the allowlist still listed. Its pipelines passed, but the next master pipeline failed:

• The MR changed only spec files, so Danger added pipeline:spec-only.
• Its tier-3 pipeline stayed predictive and selected no unit specs. The validator is a unit spec, so it did not run.
• scripts/pipeline/pre_merge_checks.rb accepts a predictive pipeline when the name includes spec-only.

A stale path has no effect at runtime: it only scopes an entry to a file that no longer runs. A stale entry is a smaller cost than a broken master.

Another option was a tests.yml mapping from feature specs to the validator. That keeps the check, but it depends on predictive selection treating deleted files as changes. It also adds one more rule to maintain. This MR takes the simpler path.

How to set up and validate locally

bundle exec rspec spec/support_specs/browser_console_allowlist_spec.rb

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

References

• Added the check: !256639 (merged)
• Deleted a listed spec and broke master: !260064 (merged)
• Fixed master by removing the stale path: !261895 (merged)
• Failure seen in this MR pipeline: !259881 (comment 4007677774)