Revert Pest 4 constraint, tests are not PHPUnit 12 compatible

The tests use getMockBuilder(), setMethodsExcept(), withConsecutive()
and other APIs that were removed or made protected in PHPUnit 12.
Pest 2 supports PHP 8.2-8.5 fine.

Author: freekmurze

composer.json

@@ -32,7 +32,7 @@
     },
     "require-dev": {
         "laravel/pint": "^1.10.1",
-        "pestphp/pest": "^2.6.3|^4.0",
+        "pestphp/pest": "^2.6.3",
         "phpstan/phpstan": "^1.10.16"
     },
     "autoload": {