Fixed options passed to conversation API without "conversationId" throwing (#1480)

Signed-off-by: Whit Waldo <[email protected]>

Author: WhitWaldo

src/Dapr.AI/Conversation/DaprConversationClient.cs

@@ -77,7 +77,11 @@ public override async Task<DaprConversationResponse> ConverseAsync(string daprCo
 
         if (options is not null)
         {
-            request.ContextID = options.ConversationId;
+            if (options.ConversationId is not null)
+            {
+                request.ContextID = options.ConversationId;
+            }
+
             request.ScrubPII = options.ScrubPII;
 
             foreach (var (key, value) in options.Metadata)