Bugfix: fix incorrect type-check

Author: tvdijen

src/Auth/Source/Ldap.php

@@ -129,9 +129,7 @@ protected function loginSasl(string $username, #[\SensitiveParameter]string $pas
         }
 
         /* Verify the credentials */
-        if (!is_null($sasl_args)) {
-            Assert::isArray($sasl_args);
-
+        if (!empty($sasl_args)) {
             $this->connector->saslBind(
                 $dn,
                 $password,