fix: Prevent crash when unregistering listener for a null sensor

Ref: #6

Author: UmerCodez

data/src/main/java/com/github/umercodez/sensorspot/data/sensoreventprovider/SensorEventProviderImp.kt

@@ -83,7 +83,10 @@ class SensorEventProviderImp(
     override fun stopProvidingEvents() {
 
         for (sensorType in _sensorTypes) {
-            sensorManager.unregisterListener(this,sensorManager.getDefaultSensor(sensorType))
+            val sensor = sensorManager.getDefaultSensor(sensorType)
+
+            if (sensor != null)
+                sensorManager.unregisterListener(this, sensor)
         }
 
     }