Fix AudioStreamPlayer2D/3D's `get_playback_position` returning `0` right after calling `seek`

scene/2d/audio_stream_player_2d.cpp

@@ -253,6 +253,9 @@ bool AudioStreamPlayer2D::is_playing() const {
 }
 
 float AudioStreamPlayer2D::get_playback_position() {
+	if (setplay.get() >= 0) {
+		return setplay.get(); // play() has been called this frame, but no playback exists just yet.
+	}
 	return internal->get_playback_position();
 }
 

scene/3d/audio_stream_player_3d.cpp

@@ -582,6 +582,9 @@ bool AudioStreamPlayer3D::is_playing() const {
 }
 
 float AudioStreamPlayer3D::get_playback_position() {
+	if (setplay.get() >= 0) {
+		return setplay.get(); // play() has been called this frame, but no playback exists just yet.
+	}
 	return internal->get_playback_position();
 }