Default accel Z direction value to +9.8

Default the accelerometer defaut Z value to +9.8 to indicate a
more 'natural' resting position of flat with screen up for the
device.

Bug: 242736284
Test: Presubmits, vts VtsHalSensorsV2_0TargetTest.
Change-Id: I92357119173dbc99a0a6665de5d733286ac30c3e
diff --git a/sensors/aidl/default/Sensor.cpp b/sensors/aidl/default/Sensor.cpp
index 62193d6..3bdd8b6 100644
--- a/sensors/aidl/default/Sensor.cpp
+++ b/sensors/aidl/default/Sensor.cpp
@@ -223,7 +223,7 @@
     EventPayload::Vec3 vec3 = {
             .x = 0,
             .y = 0,
-            .z = -9.8,
+            .z = 9.8,
             .status = SensorStatus::ACCURACY_HIGH,
     };
     payload.set<EventPayload::Tag::vec3>(vec3);