fix: call to static method on an unknown class

src/QUI/ERP/Process.php

@@ -891,6 +891,10 @@ public function getSalesOrders(): array
             return [];
         }
 
+        if (!class_exists('QUI\ERP\SalesOrders\Handler')) {
+            return [];
+        }
+
         $result = [];
 
         try {