Fix conflict with class names

[franmomu]

Subject

There is a conflict with the class names.

Ref: sonata-project/SonataAdminBundle#6264

I am targeting this branch, because this is BC.

Changelog

### Fixed
- Fixed conflict with class names.

[phansys]

My bad!

I'd use ForwardCompatibleSonataTwigBundle instead, since "Symfony" is not bringing anything related to the purpose of the alias, but not really a blocker.

[phansys]

In order to fix the build, could also please update the imported class here?

twig-extensions/tests/App/AppKernel.php

Line 16 in 5df1504

use Sonata\Doctrine\Bridge\Symfony\Bundle\SonataDoctrineBundle;

[phansys]

Thank you @franmomu!