[HWC3] VTS client updates for onRefreshRateChangedDebug callback
And for setRefreshRateChangedCallbackDebugEnabled

This does not add any implementation for the VTS code.
Implementation will be added with the VTS tests as a followup.

Test: Device boots
BUG: 202734676
Change-Id: If47bbcf87698b346907b3bc1903908ff0a63203f
diff --git a/graphics/composer/aidl/vts/GraphicsComposerCallback.h b/graphics/composer/aidl/vts/GraphicsComposerCallback.h
index e54da34..9c3bc70 100644
--- a/graphics/composer/aidl/vts/GraphicsComposerCallback.h
+++ b/graphics/composer/aidl/vts/GraphicsComposerCallback.h
@@ -55,6 +55,8 @@
             const ::aidl::android::hardware::graphics::composer3::VsyncPeriodChangeTimeline&
                     in_updatedTimeline) override;
     virtual ::ndk::ScopedAStatus onVsyncIdle(int64_t in_display) override;
+    virtual ::ndk::ScopedAStatus onRefreshRateChangedDebug(
+            const RefreshRateChangedDebugData&) override;
 
     mutable std::mutex mMutex;
     // the set of all currently connected displays