refactor: remove unnecessary transpositions

[charSLee013]

Content:

This PR addresses the issue of redundant transposition operations:

1. The original DVAE forward method included a transpose operation:

  dec_out = self.out_conv(
      self.decoder(
          input=vq_feats.transpose_(1, 2), <- here
      ).transpose_(1, 2),   <- and here
  )

2. This transpose was then repeated in the DVAEDecoder forward method:

def forward(self, input: torch.Tensor, conditioning=None) -> torch.Tensor:
    # B, T, C
    x = input.transpose_(1, 2) <- again
    ...
    return x.transpose_(1, 2) <-  also extraneous transpose