Adding schedule throws internal server error (500) for a schedule with invalid cron expression
Description
When a user tries to add a schedule with invalid cron expression the response code is 500 (Internal Server Error) we should change this to something which represents the bad request from the user's side.
When a user tries to add a schedule with invalid cron expression the response code is 500 (Internal Server Error) we should change this to something which represents the bad request from the user's side.