Add conductivity sensor to bthome (#124312)

* Add conductivity sensor to bthome

* Update icons.json

* Update sensor.py

homeassistant/components/bthome/sensor.py

@@ -27,6 +27,7 @@ from homeassistant.const import (
     PERCENTAGE,
     SIGNAL_STRENGTH_DECIBELS_MILLIWATT,
     EntityCategory,
+    UnitOfConductivity,
     UnitOfElectricCurrent,
     UnitOfElectricPotential,
     UnitOfEnergy,
@@ -356,6 +357,16 @@ SENSOR_DESCRIPTIONS = {
         native_unit_of_measurement=UnitOfVolume.LITERS,
         state_class=SensorStateClass.TOTAL,
     ),
+    # Conductivity (µS/cm)
+    (
+        BTHomeSensorDeviceClass.CONDUCTIVITY,
+        Units.CONDUCTIVITY,
+    ): SensorEntityDescription(
+        key=f"{BTHomeSensorDeviceClass.CONDUCTIVITY}_{Units.CONDUCTIVITY}",
+        device_class=SensorDeviceClass.CONDUCTIVITY,
+        native_unit_of_measurement=UnitOfConductivity.MICROSIEMENS,
+        state_class=SensorStateClass.MEASUREMENT,
+    ),
 }