rpc: websocket should respect the "HTTP_PROXY" by default (#27264)

rpc: the default dialer for websocket should respect the proxy environment variables like "HTTP_PROXY"

rpc/websocket.go

@@ -224,6 +224,7 @@ func newClientTransportWS(endpoint string, cfg *clientConfig) (reconnectFunc, er
 			ReadBufferSize:  wsReadBuffer,
 			WriteBufferSize: wsWriteBuffer,
 			WriteBufferPool: wsBufferPool,
+			Proxy:           http.ProxyFromEnvironment,
 		}
 	}