clear previous values of PublishDataRequest FFI Request object (#150)

Author: s-hamdananwar

Runtime/Scripts/Participant.cs

@@ -332,6 +332,11 @@ private unsafe void PublishData(byte* data, int len, IReadOnlyCollection<string>
 
             var publish = request.request;
             publish.LocalParticipantHandle = (ulong)Handle.DangerousGetHandle();
+
+            // Clear previous values of conditional fields
+            publish.DestinationIdentities.Clear();
+            publish.ClearTopic();
+
             publish.Reliable = reliable;
 
             if (destination_identities is not null)