arduino/netsender: distinguish different alarm states

The `updateMode` function calls the `request` function which has the side effect of clearing the alarm, even though the device may still be in the low voltage alarm state. This confusion arises because there is only a single alarm state, represented by the **Alarmed** X pin that encompasses both network alarms and low voltage alarms.

There needs to be a way to distinguish different alarm states, to avoid the low voltage alarm from being cleared when the intention is to just clear a network alarm.