fix: keep confirmation email flag schema compatible

Signed-off-by: Dmitry Tretyakov <dtretyakov@gmail.com>

Author: dtretyakov

lib/Migration/Version050300Date20260413233000.php

@@ -34,7 +34,7 @@ public function changeSchema(IOutput $output, Closure $schemaClosure, array $opt
 
 		if (!$table->hasColumn('confirmation_email_enabled')) {
 			$table->addColumn('confirmation_email_enabled', Types::BOOLEAN, [
-				'notnull' => true,
+				'notnull' => false,
 				'default' => 0,
 			]);
 			$changed = true;