Fix DownloadHandlerTest: restore MappingNotFoundException/NoFileFoundException imports from 3.x

Co-authored-by: garak <179866+garak@users.noreply.github.com>

Author: Copilot

tests/Handler/DownloadHandlerTest.php

@@ -6,6 +6,8 @@
 use PHPUnit\Framework\MockObject\MockObject;
 use Symfony\Component\HttpFoundation\StreamedResponse;
 use Vich\TestBundle\Entity\Product;
+use Vich\UploaderBundle\Exception\MappingNotFoundException;
+use Vich\UploaderBundle\Exception\NoFileFoundException;
 use Vich\UploaderBundle\Handler\DownloadHandler;
 use Vich\UploaderBundle\Mapping\PropertyMappingFactoryInterface;
 use Vich\UploaderBundle\Mapping\PropertyMappingInterface;