Celery tasks should use return Task.replace instead of raise Task.replace

[pt2302]

Description/Context

Similarly to #2312, recent versions of Celery require return Task.replace whereas previously raise Task.replace was preferred.

For context, compare
https://docs.celeryq.dev/en/3.0/reference/celery.app.task.html?highlight=raise%20self.replace#celery.app.task.Task.replace
and
https://docs.celeryq.dev/en/stable/reference/celery.app.task.html#celery.app.task.Task.replace

Plan/Design

Update any tasks that use raise Task.replace, which includes the following tasks:
https://github.com/mitodl/ocw-studio/blob/master/content_sync/tasks.py
https://github.com/mitodl/ocw-studio/blob/master/ocw_import/tasks.py
https://github.com/mitodl/ocw-studio/blob/master/gdrive_sync/tasks.py
https://github.com/mitodl/ocw-studio/blob/master/videos/tasks.py