Update data_cfg.py

add @property to def standardize_audio(self) -> bool ## What does this PR do? Here is a bug with the function. when we call `self.cfg.standardize_audio`, it always return true. see https://github.com/facebookresearch/fairseq/blob/main/fairseq/data/audio/speech_to_text_dataset.py#L244-L248 ``` if self.cfg.use_audio_input: source = torch.from_numpy(source).float() if self.cfg.standardize_audio: with torch.no_grad(): source = F.layer_norm(source, source.shape) ``` I think the function need a `@property`.