Send heartbeat package to keep serial alive (#732)

* Send heartbeat package to keep the serial connection alive

* Update meshDevice.ts

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Co-authored-by: philon- <philon-@users.noreply.github.com>

packages/web/src/components/PageComponents/Connect/Serial.tsx

@@ -43,6 +43,9 @@ export const Serial = ({ closeDialog }: TabElementProps) => {
     device.addConnection(connection);
     subscribeAll(device, connection, messageStore);
 
+    const HEARTBEAT_INTERVAL = 5*60*1000;
+    connection.setHeartbeatInterval(HEARTBEAT_INTERVAL);
+
     closeDialog();
   };