Revert "Update chat-csharp.md"

This reverts commit 047cb18.

Revert commit in #70957
to resolve merge conflict in repo sync PR
#71584

Author: ktoliver

articles/communication-services/quickstarts/chat/includes/chat-csharp.md

@@ -107,7 +107,7 @@ Use `SendMessage` to send a message to a thread.
 - Use `senderDisplayName` to specify the display name of the sender. If not specified, empty string will be set.
 
 ```csharp
-var messageId = await chatThreadClient.SendMessageAsync(content:"hello world");
+var messageId = await chatThreadClient.SendMessageAsync(content:"hello world", type: );
 ```
 ## Get a message