Warning in drupal-check for D9 [#3264710]

Problem/Motivation

There is one warning in drupal check

 ------ --------------------------------------------------------------------- 
  Line   tests/src/Functional/LoadTest.php                                    
 ------ --------------------------------------------------------------------- 
  13     Drupal\Tests\BrowserTestBase::$defaultTheme is required. See         
         https://www.drupal.org/node/3083055, which includes recommendations  
         on which theme to use.                                               
 ------ ---------------------------------------------------------------------

Steps to reproduce

Run drupal check on module.

Proposed resolution

Add $defaultTheme in tests/src/Functional/LoadTest.php

Remaining tasks

Update tests/src/Functional/LoadTest.php

User interface changes

API changes

Data model changes

Issue fork node_read_time-3264710

Show commands

Start within a Git clone of the project using the version control instructions.

Add & fetch this issue fork’s repository

Or, if you do not have SSH keys set up on git.drupalcode.org:

Add & fetch this issue fork’s repository

3264710-warning-in-drupal-check changes, plain diff MR !2
Check out this branch for the first time

Check out existing branch, if you already have it locally