Avoid calling onVsyncGenerated when vrrConfig is not available

Test: atest VSyncPredictorTest
BUG: 318537314
Change-Id: I7705a572e761fd595298afb980b00f8638fa9763
diff --git a/services/surfaceflinger/Scheduler/VSyncPredictor.cpp b/services/surfaceflinger/Scheduler/VSyncPredictor.cpp
index 28e35de..6e12b33 100644
--- a/services/surfaceflinger/Scheduler/VSyncPredictor.cpp
+++ b/services/surfaceflinger/Scheduler/VSyncPredictor.cpp
@@ -313,7 +313,7 @@
             ? std::max(timePoint, *lastVsyncOpt + minFramePeriod - threshold)
             : timePoint;
     const auto vsyncTime = snapToVsyncAlignedWithRenderRate(baseTime);
-    if (FlagManager::getInstance().vrr_config()) {
+    if (FlagManager::getInstance().vrr_config() && mDisplayModePtr->getVrrConfig()) {
         const auto vsyncTimePoint = TimePoint::fromNs(vsyncTime);
         const Fps renderRate = mRenderRateOpt ? *mRenderRateOpt : mDisplayModePtr->getPeakFps();
         mVsyncTrackerCallback.onVsyncGenerated(vsyncTimePoint, mDisplayModePtr, renderRate);