Volume: Add AIDL placeholder implementation and vts test

Bug: 258124419
Test: atest VtsHalVolumeTargetTest

Change-Id: Ie3eaa820f94be0287ba72b7647d3d7ab8b5c70b8
diff --git a/audio/aidl/vts/Android.bp b/audio/aidl/vts/Android.bp
index f1e26ac..2532d42 100644
--- a/audio/aidl/vts/Android.bp
+++ b/audio/aidl/vts/Android.bp
@@ -116,6 +116,12 @@
 }
 
 cc_test {
+    name: "VtsHalVolumeTargetTest",
+    defaults: ["VtsHalAudioTargetTestDefaults"],
+    srcs: ["VtsHalVolumeTargetTest.cpp"],
+}
+
+cc_test {
     name: "VtsHalAECTargetTest",
     defaults: ["VtsHalAudioTargetTestDefaults"],
     srcs: ["VtsHalAECTargetTest.cpp"],