Drop useless requiresPackage guard on phpat fixture

phpat/phpat is a hard require-dev pinned to ^0.12, so it is always
installed and prefer-lowest resolves 0.12.0 — the `>= 0.12` guard can
never skip. Unlike the symfony fixtures, whose constraints span multiple
majors, there is nothing to guard against here.

Co-Authored-By: Claude Code
Claude-Session: https://claude.ai/code/session_01WqA3SLHn3vQEytN5C1KCJj

Author: janedbal

tests/Rule/DeadCodeRuleTest.php

@@ -1016,7 +1016,7 @@ public static function provideFiles(): Traversable
         yield 'provider-behat' => [__DIR__ . '/data/providers/behat.php'];
         yield 'provider-doctrine' => [__DIR__ . '/data/providers/doctrine.php'];
         yield 'provider-phpstan' => [__DIR__ . '/data/providers/phpstan.php'];
-        yield 'provider-phpat' => [__DIR__ . '/data/providers/phpat.php', self::requiresPackage('phpat/phpat', '>= 0.12')];
+        yield 'provider-phpat' => [__DIR__ . '/data/providers/phpat.php'];
         yield 'provider-eloquent' => [__DIR__ . '/data/providers/eloquent.php'];
         yield 'provider-laravel' => [__DIR__ . '/data/providers/laravel.php'];
         yield 'provider-blade' => [__DIR__ . '/data/providers/blade.php'];