Check if the form is submitted before validation

[jacquesbh]

Q	A
Branch?	1.10
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets
License	MIT

I got this error during the development of a cart related feature:

Symfony\Component\Form\Exception\LogicException:
Cannot check if an unsubmitted form is valid. Call Form::isSubmitted() before Form::isValid().

  at vendor/symfony/form/Form.php:752
  at Symfony\Component\Form\Form->isValid()
     (vendor/sylius/sylius/src/Sylius/Bundle/OrderBundle/Controller/OrderController.php:83)
  at Sylius\Bundle\OrderBundle\Controller\OrderController->saveAction(object(Request))
     (vendor/symfony/http-kernel/HttpKernel.php:157)
  at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Request), 1)
     (vendor/symfony/http-kernel/HttpKernel.php:79)
  at Symfony\Component\HttpKernel\HttpKernel->handle(object(Request), 1, true)
     (vendor/symfony/http-kernel/Kernel.php:199)
  at Symfony\Component\HttpKernel\Kernel->handle(object(Request))
     (public/index.php:25)

This PR fixes that.

We could update all controllers with the same fix but right now I prefer to change only this one since I know the behavior.

[Zales0123]

👍 especially, as it's consistent with what we have in ResourceController:updateAction

[Zales0123]

The base of this pull-request was changed, you need fetch and reset your local branch
if you want to add new commits to this pull request. Reset before you pull, else commits
may become messed-up.

Unless you added new commits (to this branch) locally that you did not push yet,
execute git fetch origin && git reset "fix/form-submitted" to update your local branch.

Feel free to ask for assistance when you get stuck 👍

[Zales0123]

Thanks, Jacques! 🎉