Rename $websiteId to $scopeId

[flancer64]

This is a definition of the "\Magento\CatalogInventory\Model\Spi\StockRegistryProviderInterface::getStockStatus" method:

/**
 * @param int $productId
 * @param int $scopeId
 * @return \Magento\CatalogInventory\Api\Data\StockStatusInterface
 */
public function getStockStatus($productId, $scopeId);

Wrong variable name was used for this data in the file Stock.php

[ishakhsuvarov]

@flancer64 Thank you for your contribution