Heiman HS2WD-E siren: state.alert always remains at "none"

It may be came from the DDF that @Swoop gave in the other thread : https://forum.phoscon.de/t/heiman-warningdevice-ef-3-0-siren-no-battery-and-tampered-status/2346/5

{
“type”: “ZHAAlarm”,
“restapi”: “/sensors”,
“uuid”: [
“$address.ext”,
“0x01”,
“0x0500

And it’s the same in PR #6397