fix: add check for duplicate Registrar Auto-Discovery runs

[kenjis]

Description
See #9069

Any Registrar class should be a class that simply returns an array without side effects.
If a Registrar file instantiates any Config class, it runs Auto-Discovery again during Auto-Discovery, and duplicate runs are not expected.

This PR checks for duplicate Registrar Auto-Discovery runs, and throws Exception.

How to Test

<?php

namespace Config;

class Registrar
{
    public static function hack(): void
    {
        $config = config('Cache');

        // Does something.
    }
}

Registrar::hack(); // Bad. When this class is loaded, Config\Cache will be instantiated.

$ ./spark config:check App
PHP Fatal error:  Uncaught CodeIgniter\Exceptions\ConfigException: During Auto-Discovery of Registrars, "Config\Cache" executes Auto-Discovery again. "APPPATH/Config/Registrar.php" seems to have bad code. in /.../CodeIgniter4/system/Config/BaseConfig.php:246
Stack trace:
...

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

[michalsn]

I think this change makes sense. Just waiting for a changelog to approve.

[kenjis]

Added the docs.

[kenjis]

Is it better to send to 4.6 branch?

[neznaika0]

Maybe not, we don't know how many people use registrar, I think it's not very critical to have duplicates. The longer we wait for 4.6, the more we need to update

[michalsn]

Oops... I thought this change was for the 4.6 branch. Well, IMO we should make this change in 4.6.

Bonfire is probably relatively popular, so if we "fix" this problem in a patch release, we will make all applications that rely on it broken. Targeting v4.6 will give time for the project to work out a fix.

There may be other projects that use a similar hack. Minor releases in the CI4 world have made everyone accustomed to carefully reviewing the change log or upgrade notes.

[kenjis]

Okay. Changed target to 4.6.

[michalsn]

Thanks!

[kenjis]

Thank you all for your reviews!