Fix fields margin for shop module add/edit form

assets/cp.styles.css

@@ -1213,8 +1213,8 @@ div.wysiwyg.focused {
 		margin-bottom: 0px;
 	}
 
-	.data-form.shop-add .form-group.n12,
-	.data-form.shop-modify .form-group.n12 {
+	.data-form.shop-add .form-group.n15,
+	.data-form.shop-modify .form-group.n15 {
 		margin-bottom: 0px;
 	}