gauges: set as disconnected if no data

src/api_interface.rs

@@ -214,6 +214,7 @@ impl TeslaInterface {
             state.charge_state = Some(new_charge_state);
         } else {
             TESLA_ONLINE.set(0);
+            self.charging_state.set(ChargingState::Disconnected);
             match self.state.write() {
                 Ok(mut state) => {
                     state.charge_state = None;