bug #281 Fix of SymfonyForm error (oallain, GSadee)

This PR was merged into the 1.5 branch.

Discussion
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| Q               | A
| --------------- | -----
| Branch?         | 1.5
| Bug fix?        | yes
| New feature?    | no
| Related tickets | 


Fix of error :
```
request.CRITICAL: Uncaught PHP Exception Symfony\Component\Form\Exception\LogicException: "Cannot check if an unsubmitted form is valid. Call Form::isSubmitted() before Form::isValid()." at /home/site/vendor/symfony/form/Form.php line 765 {"exception":"[object] (Symfony\\Component\\Form\\Exception\\LogicException(code: 0): Cannot check if an unsubmitted form is valid. Call Form::isSubmitted() before Form::isValid(). at /home/site/vendor/symfony/form/Form.php:765)"} []
```

Commits
-------

250c404 Fix of SymfonyForm error
a88d022 Merge branch '1.5' into oallain-patch-1

src/Controller/PayPalOrderItemController.php

@@ -39,7 +39,7 @@ public function createFromProductDetailsAction(Request $request): Response
 
         $form = $form->handleRequest($request);
 
-        if (!$form->isValid()) {
+        if ($form->isSubmitted() && !$form->isValid()) {
             return new RedirectResponse((string) $request->headers->get('referer'));
         }