fix: Failing tests
fix: Failing tests

* Test 'Asynchronous_ProcessingTasks_NotSet' was setting the wrong
  setting. It was setting 'Synchronous.ProcessingTasks' instead of
  'Asynchronous.ProcessingTasks'
* 'Synchronous.ProcessingTasks' is now allowed to be 0 (zero) and test
  'Synchronous_ProcessingTasksEqualsZero_IsAllowed' is therefore
  changed to reflect this

chriscena/Helsenorge.Messaging,ehelse/Helsenorge.Messaging