[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/VtsComposerClient.h b/graphics/composer/aidl/vts/VtsComposerClient.h
index 27788e7..aee46d2 100644
--- a/graphics/composer/aidl/vts/VtsComposerClient.h
+++ b/graphics/composer/aidl/vts/VtsComposerClient.h
@@ -196,6 +196,9 @@
 
     bool verifyComposerCallbackParams();
 
+    ndk::ScopedAStatus setRefreshRateChangedCallbackDebugEnabled(int64_t /* display */,
+                                                                 bool /* enabled */);
+
     // Keep track of displays and layers. When a test fails/ends,
     // the VtsComposerClient::tearDown should be called from the
     // test tearDown to clean up the resources for the test.