#13434: Fix strict type checking for legacy code

Author: Volodymyr Kublytskyi

dev/tests/static/testsuite/Magento/Test/Php/_files/blacklist/strict_type.txt

@@ -1 +1,9 @@
 # Format: <componentType=module|library|theme|language|*> <componentName> <globPattern> or simply <globPattern>
+
+app/code/Magento/CatalogImportExport/Model/Import/Product.php
+app/code/Magento/ImportExport/Controller/Adminhtml/Import/Download.php
+app/code/Magento/ImportExport/Model/Import/SampleFileProvider.php
+app/code/Magento/CatalogInventory/Model/StockManagement.php
+app/code/Magento/CatalogInventory/Observer/ItemsForReindex.php
+app/code/Magento/CatalogInventory/Observer/SubtractQuoteInventoryObserver.php
+app/code/Magento/Store/Api/Data/WebsiteInterface.php