app.py is overlooking 404 (and probably other) statuses

With the new implementation of retry requests, we have noticed that the current request is overlooking when a 404 status is returned. In this case, it is trying to access and process trials that do not exist.

https://github.com/stanfordnmbl/opencap-core/blob/9d139da25577db51bdc8e90d1c9856a86f48605d/app.py#L152
