Fix infinite load on task reassign

Steps to reproduce:

• Given 3 users, login as User1, and start a Parallel Review workflow on a document, assigning it to User2.
• Login as User2 and navigate to the assigned task.
• Reassign to User3.
  => Page displays the task.
  => Page loads infinitely.
  => Error in console:

  https://nightly-rainforest.nuxeo.com/nuxeo/api/v1/task/ab43eedf-e3e7-4acd-a877-a9f351f17444
  Failed to load resource: the server responded with a status of 403 ()
  

Workaround:
Refreshing the page fixes the problem and displays the message:

You don't have any tasks to process at the moment.