Fa005 submissions file link in notifications (#298)

* fix: unsigned url in form email

* fix: signed file link in email

* fix: use limit function for file  label name

* feat: use signed url  for files in email and csv export

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Co-authored-by: Julien Nahum <julien@nahum.net>

app/Notifications/Forms/FormSubmissionNotification.php

@@ -49,7 +49,8 @@ class FormSubmissionNotification extends Notification implements ShouldQueue
         $formatter = (new FormSubmissionFormatter($this->event->form, $this->event->data))
             ->showHiddenFields()
             ->createLinks()
-            ->outputStringsOnly();
+            ->outputStringsOnly()
+            ->useSignedUrlForFiles();
 
         return (new MailMessage)
             ->replyTo($this->getReplyToEmail($notifiable->routes['mail']))