Implement Stylus Prediction Metrics

Fills out the implementation and tests for MotionPredictorMetricsManager.

(Cherry pick of ag/23861881 from udc-qpr-dev)

Test: atest frameworks/native/libs/input/tests/MotionPredictorMetricsManager_test.cpp
Test: Manual testing on-device, computed metric values seem reasonable.

Bug: 268245099
Change-Id: Iec18415de9c3070f2b285c5c82f5a5e0ceaaf471
diff --git a/libs/input/MotionPredictor.cpp b/libs/input/MotionPredictor.cpp
index 0961a9d..b5a5e72 100644
--- a/libs/input/MotionPredictor.cpp
+++ b/libs/input/MotionPredictor.cpp
@@ -137,10 +137,7 @@
 
     // Pass input event to the MetricsManager.
     if (!mMetricsManager) {
-        mMetricsManager =
-                std::make_optional<MotionPredictorMetricsManager>(mModel->config()
-                                                                          .predictionInterval,
-                                                                  mModel->outputLength());
+        mMetricsManager.emplace(mModel->config().predictionInterval, mModel->outputLength());
     }
     mMetricsManager->onRecord(event);