Changed the SendFinalEmailToReceiversAsync method to use a sequential `foreach` loop instead of `Task.WhenAll` for sending history commands. Added a null check for receiver emails to prevent potential exceptions.
- Replaced manual FinishEnvelopeJob Quartz setup with ScheduleJobDefault extension - Added scheduling for EnvelopeTaskApiJob - Updated using directives to include EnvelopeGenerator.Finalizer namespace - Improved maintainability by removing redundant Quartz configuration logic
