CSD: return interface for messages to audio server

Whenever the AudioService registers for receiving sound dose callbacks from the
native side, the native sends back the ISoundDose interface.

Test: logs, dumpsys and UT
Bug: 257238734
Change-Id: I5605196e8be91f00a7fbcf65573dfabe6e5c03d3
diff --git a/services/audioflinger/MelReporter.h b/services/audioflinger/MelReporter.h
index 3625a86..f73b3d6 100644
--- a/services/audioflinger/MelReporter.h
+++ b/services/audioflinger/MelReporter.h
@@ -44,7 +44,7 @@
     // For now only support internal MelReporting
     [[nodiscard]] bool isHalReportingEnabled() const { return false; }
 
-    void registerSoundDoseCallback(const sp<media::ISoundDoseCallback>& callback);
+    sp<media::ISoundDose> getSoundDoseInterface(const sp<media::ISoundDoseCallback>& callback);
 
     std::string dump();