Fix newaddress request

Sources/Stratis.Bitcoin.Features.Wallet/Models/DeStreamRequestModel.cs

+using System.ComponentModel.DataAnnotations;
+
+namespace Stratis.Bitcoin.Features.Wallet.Models
+{
+    public class GetNewAddressModel : RequestModel
+    {
+        /// <summary>
+        /// The name of the wallet from which to get the address.
+        /// </summary>
+        [Required]
+        public string WalletName { get; set; }
+
+        /// <summary>
+        /// The name of the account for which to get the address.
+        /// </summary>
+        [Required]
+        public string AccountName { get; set; }
+    }
+}
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