refactor(rector): apply safe modernizations in Pkcs12Handler

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

lib/Handler/SignEngine/Pkcs12Handler.php

@@ -247,7 +247,7 @@ private function hasLibreSignCaId(array $parsed): bool {
 		}
 
 		foreach ($organizationalUnits as $ou) {
-			$ou = trim($ou);
+			$ou = trim((string)$ou);
 			if ($this->caIdentifierService->isValidCaId($ou, $instanceId)) {
 				return true;
 			}