Add fallback for sensor identification in ddc

If a display device config was specified but without a valid ambient light sensor, it would fall back to Sensor.TYPE_LIGHT rather than the specified one in config.xml. This change fixes that.

Bug: 187130675
Test: adb shell dumpsys display | grep DisplayDeviceConfig
Test: com.android.server.display
Change-Id: I5b3f71a7c32055dbbd43d8fd139cfa7d09b9b3c4

services/core/java/com/android/server/display/DisplayDeviceConfig.java

@@ -689,6 +689,8 @@ public class DisplayDeviceConfig {
         if (sensorDetails != null) {
             mAmbientLightSensor.type = sensorDetails.getType();
             mAmbientLightSensor.name = sensorDetails.getName();
+        } else {
+            loadAmbientLightSensorFromConfigXml();
         }
     }