Fix debug dump-ws crashing the controller

When ws was updated to version 8 it came with a breaking change where
message data was no longer utf8 decoded from binary to a string.  The
main codepath handling messages was updated to handle this but the ws
dump path was not resulting in the controller crashing when receiving
a message that is then forwarded to the dumper without decoding.

Fix by decoding the message in the dump-ws path.

packages/controller/src/WsServer.ts

@@ -107,7 +107,7 @@ export default class WsServer {
 		socket.on("message", (message: WebSocket.RawData) => {
 			wsMessageCounter.labels("in").inc();
 			if (!socket.clusterio_ignore_dump) {
-				this.controller.debugEvents.emit("message", { direction: "in", content: message });
+				this.controller.debugEvents.emit("message", { direction: "in", content: message.toString("utf8") });
 			}
 		});
 		let originalSend = socket.send;