Validate IAfEffectHandle before access virtual methods

Bug: 290218127
Test: atest DeviceEffectTest#testIsEffectSupportedForDevice --iterations 50
Change-Id: I2e427a80e19c2e5987673bfd014a5da5566f4a24
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 1e59bf8..22358db 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -4314,7 +4314,7 @@
 
     response->id = idOut;
     response->enabled = enabledOut != 0;
-    response->effect = handle->asIEffect();
+    response->effect = handle.get() ? handle->asIEffect() : nullptr;
     response->desc = VALUE_OR_RETURN_STATUS(
             legacy2aidl_effect_descriptor_t_EffectDescriptor(descOut));