Fix null dereference read in android::hardware::bluetooth::hci::H4Protocol::Send

Bug: 276375037
Test: atest VtsHalBluetoothTargetTest
Change-Id: Ib9f99a75a97538899ac64a3c02fff1ec5804a0e6
diff --git a/bluetooth/aidl/default/BluetoothHci.h b/bluetooth/aidl/default/BluetoothHci.h
index 85aafc8..477cc5c 100644
--- a/bluetooth/aidl/default/BluetoothHci.h
+++ b/bluetooth/aidl/default/BluetoothHci.h
@@ -66,8 +66,9 @@
   ::android::hardware::bluetooth::async::AsyncFdWatcher mFdWatcher;
 
   int getFdFromDevPath();
-  void send(::android::hardware::bluetooth::hci::PacketType type,
-            const std::vector<uint8_t>& packet);
+  [[nodiscard]] ndk::ScopedAStatus send(
+      ::android::hardware::bluetooth::hci::PacketType type,
+      const std::vector<uint8_t>& packet);
   std::unique_ptr<NetBluetoothMgmt> management_{};
 
   // Send a reset command and discard all packets until a reset is received.