fix: PHPStan errors

[kenjis]

Description
See https://github.com/CodeIgniter/phpstan-codeigniter/releases/tag/v1.4.0

  ------ ----------------------------------------------------------------------- 
  Line   system/CLI/BaseCommand.php                                             
 ------ ----------------------------------------------------------------------- 
  127    Call to function config with Config\Exceptions::class is discouraged.  
         💡 Use config('Exceptions') instead to allow overriding.               
 ------ ----------------------------------------------------------------------- 

https://github.com/codeigniter4/CodeIgniter4/actions/runs/6490312938/job/17625890673

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[MGatner]

My only qualm with this new rule is that it hides dependencies from Deptrac. I think Config is fine as a globally-available dependency so I'm not too worried about it, but I did like the easily-built dependency graph.

[kenjis]

I don't want the GitHub action check to always fail, so I'll merge it in for now.