Use LLNDK guard instead of builtin_available

APEXSUPPORT_API was a workaround when we had no support for
__ANDROID_VENDOR_API__. Since we have it now, use it instead of
builtin_available(android APEXSUPPORT_API).

Bug: 302088370
Test: CtsMediaAudioTestCases
Change-Id: I28b0e0ebab5f357a2f5cc29f244ae5494e379fbe
diff --git a/audio/aidl/default/EffectMain.cpp b/audio/aidl/default/EffectMain.cpp
index ac178b6..a300cfd 100644
--- a/audio/aidl/default/EffectMain.cpp
+++ b/audio/aidl/default/EffectMain.cpp
@@ -29,7 +29,7 @@
 static const char* kDefaultConfigName = "audio_effects_config.xml";
 
 static inline std::string config_file_path() {
-    if (__builtin_available(android AAPEXSUPPORT_API, *)) {
+    if constexpr (__ANDROID_VENDOR_API__ >= 202404) {
         AApexInfo *apexInfo;
         if (AApexInfo_create(&apexInfo) == AAPEXINFO_OK) {
             std::string apexName(AApexInfo_getName(apexInfo));