Tasks defined in workflows repository not added to task processor registry

[sentry-io]

Sentry Issue: FLAGSMITH-API-52D

KeyError: 'tasks.notify_group_of_change_request_assignment'
  File "task_processor/models.py", line 71, in callable
    return registered_tasks[self.task_identifier]

TaskProcessingError: ("No task registered with identifier '%s'. Ensure your task is decorated with @register_task_handler.", 'tasks.notify_group_of_change_request_assignment')
  File "task_processor/processor.py", line 96, in _run_task
    task.run()
  File "task_processor/models.py", line 66, in run
    return self.callable(*self.args, **self.kwargs)
  File "task_processor/models.py", line 73, in callable
    raise TaskProcessingError(

Failed to execute task 'tasks.notify_group_of_change_request_assignment'. Exception was: ("No task registered with identifier '%s'. Ensure your task is decorated with @register_task_handler.", 'tasks.notify_group_of_change_request_assignment')

[matthewelwell]

I can reproduce this by doing e.g.

poetry install --with dev,workflows --no-root
LOG_LEVEL=DEBUG python manage.py runprocessor

Inspecting the debug logs as to which tasks are registered then shows that the task defined in the workflows repository here is not correctly registered.

This seems unusual considering the fact that we explicitly load the tasks module on AppConfig.ready here