Change @OUT_RECEIVER_ID type from int to bigint

Updated the SQL query in `EnvelopeReceiverAddReadSQL.cs` to change the data type of the `@OUT_RECEIVER_ID` variable from `int` to `bigint`. This modification ensures support for larger identifier values, addressing potential limitations of the previous `int` type.

EnvelopeGenerator.Application/Common/SQL/EnvelopeReceiverAddReadSQL.cs

@@ -13,7 +13,7 @@ public class EnvelopeReceiverAddReadSQL : ISQL<Envelope>
     /// ENV_UID, EMAIL_ADRESS, SALUTATION, PHONE, 
     /// </summary>
     public string Raw => @"
-		DECLARE	@OUT_RECEIVER_ID int
+		DECLARE	@OUT_RECEIVER_ID bigint
 
 		EXEC	[dbo].[PRSIG_API_CREATE_RECEIVER]
 				{0},