[TASK] Remove ext_emconf.php from Rector paths

Exclude `ext_emconf.php` from Rector's analyzed paths to align with its deprecation and removal in favor of `composer.json`.

Author: froemken

Build/rector/rector.php

@@ -25,7 +25,6 @@
         __DIR__ . '/../../Classes',
         __DIR__ . '/../../Configuration',
         __DIR__ . '/../../Tests',
-        __DIR__ . '/../../ext_emconf.php',
     ])
     ->withPreparedSets(
         deadCode: true,