If `ctx.getContentData` fails (e.g.: the contentId or revisionId does not exist), it will never emit the `PREVIEWS_FINISHED` event. This will cause the activity to never be triggered which will ensure that the nullpointer doesn't get triggered and a general exception does not get thrown.

I don't think this will make all the preview errors go away though. I'm gonna check if we can somehow ship our logfile to S3 so we have the full log when an error occurs.