fix task.py with no dest_sample_rate task; fix bug in train and infer

mengzhe.cmz

2023-04-12 1ad439f96b8cdbca98ee95b886d692dfa20e85ce

 funasr/export/models/encoder/conformer_encoder.py

@@ -61,7 +61,6 @@
                speech: torch.Tensor,
                speech_lengths: torch.Tensor,
                ):
        speech = speech * self._output_size ** 0.5
        mask = self.make_pad_mask(speech_lengths)
        mask = self.prepare_mask(mask)
        if self.embed is None: