Fix custom code notify stock

\app\code\Blueskytechco\CustomCatalog\Controller\Notifystock\Save.php \app\code\Blueskytechco\CustomCatalog\ViewModel\Catalog.php \app\code\Blueskytechco\CustomCatalog\view\frontend\layout\catalog_product_view.xml \app\code\Blueskytechco\CustomCatalog\view\frontend\templates\product\view\out_stock.phtml \app\code\Blueskytechco\CustomCatalog\view\frontend\web\js\customlayout.js