Refactor envelope receiver command and response handling

- Updated `CreateEnvelopeReceiverCommand` to specify response type for `IRequest`.
- Enhanced `CreateEnvelopeReceiverCommandHandler` to use `AutoMapper` and return `CreateEnvelopeReceiverResponse`.
- Modified `Handle` method to map envelope data and populate recipient lists.
- Changed `CreateEnvelopeReceiverResponse` to inherit from `CreateEnvelopeResponse` and added new properties.
- Adjusted mapping profile to map `Envelope` to `CreateEnvelopeReceiverResponse`.
- Created new mapping profile for `Receiver` to `ReceiverReadDto`.

EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeMappingProfile.cs

@@ -1,4 +1,5 @@
 using AutoMapper;
+using EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
 using EnvelopeGenerator.Domain.Entities;
 
 namespace EnvelopeGenerator.Application.Envelopes.Commands;
@@ -13,6 +14,6 @@ public class CreateEnvelopeMappingProfile : Profile
     /// </summary>
     public CreateEnvelopeMappingProfile()
     {
-        CreateMap<Envelope, CreateEnvelopeResponse>();
+        CreateMap<Envelope, CreateEnvelopeReceiverResponse>();
     }
 }