Fix EZP-23486: don't fallback to legacy on front-end preview
Merge pull request #1042 from joaoinacio/EZP-23486_sf_preview

Fix EZP-23486: don't fallback to legacy on front-end preview
Update LegacyResponseManagerTest.php

Comply to Symfony commit: https://github.com/symfony/symfony/commit/96e7b016023412970031ab1a60c51855a9e6304e