AudioServer's is_playback_active method is not exposed in godot-cpp

When trying to build the Godot SteamAudio GDExtension, I get the following errors. Examination of the generated files shows that indeed this method is not exposed for GDExtension, despite being in the original AudioServer source code:
`
extension/src/audio_stream_player_steamaudio.cpp: In member function 'void AudioStreamPlayerSteamAudio::_notification(int)':
extension/src/audio_stream_player_steamaudio.cpp:51:91: error: 'class godot::AudioServer' has no member named 'is_playback_active'
51 | if (playback.is_valid() && !AudioServer::get_singleton()->is_playback_active(playback) && !AudioServer::get_singleton()->is_playback_paused(playback)) {
| ^~~~~~~~~~~~~~~~~~
extension/src/audio_stream_player_steamaudio.cpp:51:154: error: 'class godot::AudioServer' has no member named 'is_playback_paused'
51 | if (playback.is_valid() && !AudioServer::get_singleton()->is_playback_active(playback) && !AudioServer::get_singleton()->is_playback_paused(playback)) {
| ^~~~~~~~~~~~~~~~~~
`