Make optional the required fieds in an optional inner form if not using the inner form

Using the sample project, since 10.10-HF26, when using a create form, an optional "create additional resource" is now mandatory.
The optional screen should remain optional.

First, create a Dossier Convention, then enter the creation form of the Convention type

Observation with 10.10-HF25 + project:

• Filling in the "Convention" form fully => The "Créer" button works right away

Observation with 10.10-HF26 + project;

• Filling in the "Convention" form fully and hitting the "Créer" button results in no action
• If filling in the "ajout co-contractant" form and clicking "ajouter" => calls via POST http://localhost:8080/nuxeo/api/v1/automation/AC_Convention_CreerCoContractantBouton => then clicking "annuler" in the "ajout co-contractant" form
• Then hitting the "Créer" button in the Convention results in Convention being created

Same with 10.10-HF33