Updated IEnvelopeHistoryRepository and IEnvelopeHistoryService
interfaces to replace int? status with Constants.EnvelopeStatus?
status in CountAsync and ReadAsync methods. Adjusted
ReadHistoryQueryHandler and EnvelopeHistoryService methods to
accommodate the new type. Modified EnvelopeHistoryRepository
to accept Constants.EnvelopeStatus? in relevant methods and
marked it as obsolete, suggesting a future refactor.