fix(client): respect blocking configuration in send_message

Signed-off-by: Luca Muscariello <muscariello@ieee.org>

Author: muscariello

src/a2a/client/base_client.py

@@ -80,6 +80,7 @@ async def send_message(
 
         if configuration:
             config.MergeFrom(configuration)
+            config.blocking = configuration.blocking
 
         send_message_request = SendMessageRequest(
             message=request, configuration=config, metadata=request_metadata