Add null check in PowerAdvisor::supportsPowerHintSession

halWrapper can be null in some cases.

Bug: 240341302
Test: ARCVM boots
Change-Id: I768820c31f1ae8929851212f5ecb310e2b3a9098
(cherry picked from commit 65a2c197a4223528a51d13b64b0b6e03d0f65008)
diff --git a/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp b/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
index 77dda6c..b9d4753 100644
--- a/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
+++ b/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
@@ -187,7 +187,7 @@
     if (!mSupportsPowerHint.has_value()) {
         std::lock_guard lock(mPowerHalMutex);
         HalWrapper* const halWrapper = getPowerHal();
-        mSupportsPowerHint = halWrapper->supportsPowerHintSession();
+        mSupportsPowerHint = halWrapper && halWrapper->supportsPowerHintSession();
     }
     return *mSupportsPowerHint;
 }