Updated RedirectAction so that it makes use of the not found short url options

module/Core/src/Action/PixelAction.php

@@ -4,12 +4,21 @@ declare(strict_types=1);
 namespace Shlinkio\Shlink\Core\Action;
 
 use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\RequestHandlerInterface;
 use Shlinkio\Shlink\Common\Response\PixelResponse;
 
 class PixelAction extends AbstractTrackingAction
 {
-    protected function createResp(string $longUrl): ResponseInterface
+    protected function createSuccessResp(string $longUrl): ResponseInterface
     {
         return new PixelResponse();
     }
+
+    protected function createErrorResp(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): ResponseInterface {
+        return new PixelResponse();
+    }
 }