LoudnessEnhancer: Add AIDL implementation and its unit test

Added AIDL implementation for LoudnessEnhancer audio effect
parameters and its unit test.

Bug: 258124419
Test: atest VtsHalLoudnessEnhancerTargetTest

Change-Id: I2dfd304ca9f72383572fd1f762d41864dd73e39d
diff --git a/audio/aidl/vts/Android.bp b/audio/aidl/vts/Android.bp
index b15432e..03e9fca 100644
--- a/audio/aidl/vts/Android.bp
+++ b/audio/aidl/vts/Android.bp
@@ -70,3 +70,9 @@
     defaults: ["VtsHalAudioTargetTestDefaults"],
     srcs: ["VtsHalEqualizerTargetTest.cpp"],
 }
+
+cc_test {
+    name: "VtsHalLoudnessEnhancerTargetTest",
+    defaults: ["VtsHalAudioTargetTestDefaults"],
+    srcs: ["VtsHalLoudnessEnhancerTargetTest.cpp"],
+}