NeoModules: integrate NotaryAssisted attribute

Port the neo-project/neo-modules#884.

Signed-off-by: Anna Shaleva <[email protected]>

src/Plugins/RpcClient/Utility.cs

@@ -206,6 +206,10 @@ public static TransactionAttribute TransactionAttributeFromJson(JObject json)
                 {
                     Hash = UInt256.Parse(json["hash"].AsString())
                 },
+                TransactionAttributeType.NotaryAssisted => new NotaryAssisted()
+                {
+                    NKeys = (byte)json["nkeys"].AsNumber()
+                },
                 _ => throw new FormatException(),
             };
         }