feat(ReceiverAlreadySignedQuery): create with handler

EnvelopeGenerator.Application/EnvelopeReceivers/Queries/ReadEnvelopeReceiverQuery.cs

@@ -85,11 +85,20 @@ public record ReadEnvelopeReceiverQuery : IRequest<IEnumerable<EnvelopeReceiverD
     public ReadReceiverQuery? Receiver { get; set; }
 };
 
+/// <summary>
+/// 
+/// </summary>
 public static class Extensions
 {
-    public static Task<EnvelopeReceiverDto?> ReadEnvelopeReceiverAsync(this IMediator mediator, string key)
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="mediator"></param>
+    /// <param name="key"></param>
+    /// <returns></returns>
+    public static Task<EnvelopeReceiverDto?> ReadEnvelopeReceiverAsync(this IMediator mediator, string key, CancellationToken cancel = default)
     {
         var q = new ReadEnvelopeReceiverQuery() { Key = key };
-        return mediator.Send(q).Then(envRcvs => envRcvs.FirstOrDefault());
+        return mediator.Send(q, cancel).Then(envRcvs => envRcvs.FirstOrDefault());
     }
 }