feat: enable cpp extension standalone test case (#10)

.gnfiles/build/options.gni

@@ -0,0 +1,9 @@
+#
+# Copyright © 2024 Agora
+# This file is part of TEN Framework, an open source project.
+# Licensed under the Apache License, Version 2.0, with certain conditions.
+# Refer to the "LICENSE" file in the root directory for more information.
+#
+declare_args() {
+  ten_enable_standalone_test = false
+}