feat(layouts): add 'Single' layout option to GroupLayout and update related functionality

tests/Unit/Catalog/CatalogModelsTest.php

@@ -36,9 +36,20 @@ class CatalogModelsTest extends TestCase
             'simple',
             'simple_vertical',
             'carousel',
+            'single',
         ], GroupLayout::values());
     }
 
+    public function test_product_layout_has_all_supported_values(): void
+    {
+        $this->assertSame([
+            'row',
+            'column_with_image',
+            'column_with_cart',
+            'ticket_selector',
+        ], ProductLayout::values());
+    }
+
     public function test_attribute_maps_its_values_and_relations(): void
     {
         $attribute = new Attribute;