PHPStan "Class not found" errors during check for deprecated code on ProboCI

[barrettbaffert]

Describe the bug
The probo check for Deprecated Code has the same error twice

Internal error: Class                                                                         
'Drupal\TestTools\PhpUnitCompatibility\RunnerVersion' not found                               
Run PHPStan with --debug option and post the stack trace to:                                  
https://github.com/phpstan/phpstan/issues/new  

To Reproduce
Steps to reproduce the behavior:

1. Submit a pull request
2. Look at the "checks" section
3. View details on Deprecated Code

Expected behavior
Check fo Deprecated Code only fails if the pull request introduces non-standard code

Screenshots
If applicable, add screenshots to help explain your problem.

[joeparsons]

These PHPStan "Class not found" errors don't seem to occur when using the latest drupal-check release locally so perhaps we should see if we can apply the fix for the drupal-check TTY issue from this PR as a patch in our az-quickstart-scaffolding composer.json config until a new drupal-check release is available.