Fix exception if assets dir is missing in prod

Author: rynhndrcksn

Resources/config/asset_mapper.php

@@ -75,6 +75,7 @@
                 param('kernel.project_dir'),
                 abstract_arg('array of excluded path patterns'),
                 abstract_arg('exclude dot files'),
+                param('kernel.debug'),
             ])
 
         ->set('asset_mapper.public_assets_path_resolver', PublicAssetsPathResolver::class)