fix(BS-15981) 404 Errors using API/bpm/humanTask/TASKID

- Avoid trying to get the human task after performing an update. This
is both useless (as we do not return the new object when performing a
PUT) and buggy (as the task may have already been archived if the update
was on its state)

Cover [BS-15981](https://bonitasoft.atlassian.net/browse/BS-15981)