Fix 'DocComment.MissingShort' in FunctionalJavascript tests

Problem/Motivation

The sniff 'Drupal.Commenting.DocComment.MissingShort' is not enabled.

Steps to reproduce

Proposed resolution

Fix violations in FunctionalJavascript tests.

Remaining tasks

Make an MR.
Review.

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet