Currently we're not running Behat form builder tests on Enterprise Demo.

Goal of this task:

• adapt Form Builder tests so that they can be run on enterprise demo
• add them to "demoRegression" test suite (https://github.com/ezsystems/ezplatform-page-builder/blob/master/behat_suites.yml#L64)

TO BE DECIDED: on which versions should the tests be adapted, which depends on when will we be able to tackle this issue.