fix: precedence of command classes with the same `$name`

[kenjis]

Description This PR changes to use the first command class discovered.

In the current implementation, the last class discovered is executed. However, for CI4's behavior, if there is a command class in App\Commands, it should take precedence.

See also https://forum.codeigniter.com/showthread.php?tid=90877&pid=418854#pid418854

Checklist:

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