Refactor EnvelopeStatus usage and streamline code

- Added `EnvelopeGenerator.Domain.Constants` in multiple files, replacing `Domain.Constants.EnvelopeStatus` with `EnvelopeStatus` for improved readability.
- Modified `CreateEnvelopeCommandHandler.cs` to directly use `request.UserId`, eliminating unnecessary local variable assignment.
- Identified potential duplication in query logic within `ReceiverAlreadySignedQuery.cs`.
- Updated `IEnvelopeService`, `EnvelopeReceiverService`, and `EnvelopeService` to ensure consistent usage of the simplified `EnvelopeStatus`.
- Overall, these changes enhance code maintainability and clarity.

EnvelopeGenerator.Application/Interfaces/Services/IEnvelopeService.cs

@@ -1,7 +1,7 @@
 using DigitalData.Core.Abstraction.Application;
 using DigitalData.Core.Abstraction.Application.DTO;
 using EnvelopeGenerator.Application.Dto;
-using EnvelopeGenerator.Application.Envelopes.Queries;
+using EnvelopeGenerator.Domain.Constants;
 using EnvelopeGenerator.Domain.Entities;
 
 namespace EnvelopeGenerator.Application.Interfaces.Services;
@@ -41,5 +41,5 @@ public interface IEnvelopeService : IBasicCRUDService<EnvelopeDto, Envelope, int
     /// <param name="max_status"></param>
     /// <param name="ignore_statuses"></param>
     /// <returns></returns>
-    Task<DataResult<IEnumerable<EnvelopeDto>>> ReadByUserAsync(int userId, Domain.Constants.EnvelopeStatus? min_status = null, Domain.Constants.EnvelopeStatus? max_status = null, params Domain.Constants.EnvelopeStatus[] ignore_statuses);
+    Task<DataResult<IEnumerable<EnvelopeDto>>> ReadByUserAsync(int userId, EnvelopeStatus? min_status = null, EnvelopeStatus? max_status = null, params EnvelopeStatus[] ignore_statuses);
 }