Update modbus state when sensor fails (#49481)

.coveragerc

@@ -619,6 +619,7 @@ omit =
     homeassistant/components/modbus/modbus.py
     homeassistant/components/modbus/switch.py
     homeassistant/components/modbus/sensor.py
+    homeassistant/components/modbus/binary_sensor.py
     homeassistant/components/modem_callerid/sensor.py
     homeassistant/components/motion_blinds/__init__.py
     homeassistant/components/motion_blinds/const.py

homeassistant/components/modbus/binary_sensor.py

@@ -170,6 +170,7 @@ class ModbusBinarySensor(BinarySensorEntity):
             result = self._hub.read_discrete_inputs(self._slave, self._address, 1)
         if result is None:
             self._available = False
+            self.schedule_update_ha_state()
             return
 
         self._value = result.bits[0] & 1

homeassistant/components/modbus/sensor.py

@@ -294,6 +294,7 @@ class ModbusRegisterSensor(RestoreEntity, SensorEntity):
             )
         if result is None:
             self._available = False
+            self.schedule_update_ha_state()
             return
 
         registers = result.registers