[EnCodec] Changes for 32kHz ckpt
# What does this PR do?

Updates the EnCodec config and modelling code to allow two options for the residual connection in the Resnet block:
1. Pass the residual through a Conv1d
2. Apply the residual directly (identity)

=> this change is required to use the latest 32kHz EnCodec model in the Music Gen model (#24109). It is tested for with a fast test, and confirmed to match the original implementation.

_The documentation is not available anymore as the PR was closed or merged._