[backend] Correctif prix spécifiques

backend/controllers/ProductController.php

                         $conditionsProductPriceExist = [
                                 'id_product' => $idProduct,
                                 'id_user' => $model->id_user ? $model->id_user : null,
+                                'id_group_user' => $model->id_user_group ? $model->id_user_group : null,
                                 'id_point_sale' => $model->id_point_sale ? $model->id_point_sale : null,
                         ] ;