Refactor ShopCategory class and grid.js to improve nested field handling and code readability

autoload/admin/factory/class.ShopCategory.php

@@ -190,6 +190,7 @@ class ShopCategory
       foreach ( $title as $key => $val )
       {
         if ( $translation_id = $mdb -> get( 'pp_shop_categories_langs', 'id', [ 'AND' => [ 'category_id' => $category_id, 'lang_id' => $key ] ] ) )
+        {
           $mdb -> update( 'pp_shop_categories_langs', [
             'lang_id' => $key,
             'title' => $title[$key] != '' ? $title[$key] : null,
@@ -205,6 +206,7 @@ class ShopCategory
           ], [
             'id' => $translation_id
           ] );
+        }
         else
           $mdb -> insert( 'pp_shop_categories_langs', [
             'category_id' => (int)$category_id,