[Serve] Ignore cancel request when receving websocket.accept message (#39413) (#39626)

From application to client, it is sending `websocket.accept` message.

https://asgi.readthedocs.io/en/latest/specs/www.html#accept-send-event

Author: sihanwang41

python/ray/serve/_private/http_proxy.py

@@ -1236,7 +1236,7 @@ async def _consume_and_send_asgi_message_generator(
                         # field. Other response types (e.g., WebSockets) may not.
                         status_code = str(asgi_message["status"])
                         expecting_trailers = asgi_message.get("trailers", False)
-                    elif asgi_message["type"] == "websocket.connect":
+                    elif asgi_message["type"] == "websocket.accept":
                         is_websocket_connection = True
                     elif (
                         asgi_message["type"] == "http.response.body"