HapticGenerator: Add AIDL placeholder implementation and vts test

Bug: 258124419
Test: atest VtsHalHapticGeneratorTargetTest

Change-Id: I576eb32d64412f4eea024d49fd68d3e725483db6
diff --git a/audio/aidl/vts/Android.bp b/audio/aidl/vts/Android.bp
index 26467c9..94de0d4 100644
--- a/audio/aidl/vts/Android.bp
+++ b/audio/aidl/vts/Android.bp
@@ -80,6 +80,12 @@
 }
 
 cc_test {
+    name: "VtsHalHapticGeneratorTargetTest",
+    defaults: ["VtsHalAudioTargetTestDefaults"],
+    srcs: ["VtsHalHapticGeneratorTargetTest.cpp"],
+}
+
+cc_test {
     name: "VtsHalLoudnessEnhancerTargetTest",
     defaults: ["VtsHalAudioTargetTestDefaults"],
     srcs: ["VtsHalLoudnessEnhancerTargetTest.cpp"],