Test-only job should ignore changes to Nightwatch files

Migrated issue

Reported by: jonathan1055

Related to !292 (merged)

Problem/Motivation

The test-only changes job ' is added to the pipeline when there are just changes to nightwatch tests. This is confusing for the developer, the job is not designed to run Nightwatch tests, and is a waste of resources.

See https://git.drupalcode.org/issue/project_browser-3477343/-/jobs/3384241 for example

Proposed resolution

Tighten the rule so that only PHPUnit test files with changes will trigger the job to be added.

Remaining tasks