Refine error logs when sending pong for dYdX (#2184)

Author: davidsblom

nautilus_trader/adapters/dydx/websocket/client.py

@@ -200,7 +200,7 @@ async def send_pong(self, raw: bytes) -> None:
         try:
             await self._client.send_pong(raw)
         except WebSocketClientError as e:
-            self._log.error(str(e))
+            self._log.error(f"Failed to send pong: {e}")
 
     async def _reconnect_guard(self) -> None:
         """