feat: product variant

lib/data/models/response/order_response_model.dart

@@ -187,6 +187,7 @@ class OrderItem {
   final String? productId;
   final String? productName;
   final String? productVariantId;
+  final String? productVariantName;
   final int? quantity;
   final int? unitPrice;
   final int? totalPrice;
@@ -202,6 +203,7 @@ class OrderItem {
     this.productId,
     this.productName,
     this.productVariantId,
+    this.productVariantName,
     this.quantity,
     this.unitPrice,
     this.totalPrice,
@@ -218,6 +220,7 @@ class OrderItem {
         productId: json["product_id"],
         productName: json["product_name"],
         productVariantId: json["product_variant_id"],
+        productVariantName: json["product_variant_name"],
         quantity: json["quantity"],
         unitPrice: json["unit_price"],
         totalPrice: json["total_price"],
@@ -238,6 +241,7 @@ class OrderItem {
         "product_id": productId,
         "product_name": productName,
         "product_variant_id": productVariantId,
+        "product_variant_name": productVariantName,
         "quantity": quantity,
         "unit_price": unitPrice,
         "total_price": totalPrice,