Fix Drupal.Commenting.FunctionComment.Missing in KernelTests tests

Problem/Motivation

Working to enable the sniff Drupal.Commenting.FunctionComment.Missing.

Steps to reproduce

Proposed resolution

Fix this sniff for Kernel tests

Remaining tasks

Create an MR
Enable the sniff in phpcs.xml.dist to include KernelTests tests
Fix reported errors
Review

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet