constraint isSiret in input siret customer_form

[sococa]

Hello,


I created a module to add address form inputs to the registration form.
That's good, but I would like to add the 'isSiret' constraint to the SIRET input (customer form) from my module.
I can add the input with the constraint as follows:

    $additionalFields[] = (new FormField)
        ->setName('siret')
        ->setType('text')
        ->setLabel($this->l('N°SIRET'))
        ->setRequired(true)
        ->addConstraint('isSiret');

But obviously, the input appears twice. 

How can i simply modify the original input please ?
Thanks

ps_customregistrationfields.zip