BtAudio: Iterate reference in VTS helper

Test: atest VtsHalBluetoothAudioTargetTest
Bug: 203490261
Change-Id: Ie640c2444e523984a04378b96916d0a3e63f49cd
diff --git a/bluetooth/audio/aidl/vts/VtsHalBluetoothAudioTargetTest.cpp b/bluetooth/audio/aidl/vts/VtsHalBluetoothAudioTargetTest.cpp
index 307403b..f14bff5 100644
--- a/bluetooth/audio/aidl/vts/VtsHalBluetoothAudioTargetTest.cpp
+++ b/bluetooth/audio/aidl/vts/VtsHalBluetoothAudioTargetTest.cpp
@@ -417,7 +417,7 @@
 
   void GetA2dpOffloadCapabilityHelper(const CodecType& codec_type) {
     temp_codec_capabilities_ = nullptr;
-    for (auto codec_capability : temp_provider_capabilities_) {
+    for (auto& codec_capability : temp_provider_capabilities_) {
       auto& a2dp_capabilities =
           codec_capability.get<AudioCapabilities::a2dpCapabilities>();
       if (a2dp_capabilities.codecType != codec_type) {