updated variables in python files

Author: Dan-Flores

src/torchcodec/_core/Encoder.h

@@ -49,9 +49,6 @@ class AudioEncoder {
   UniqueSwrContext swrContext_;
   AudioStreamOptions audioStreamOptions;
 
-  // TODO-ENCODING: desiredNumChannels should just be part of an options struct,
-  // see other TODO above.
-  int desiredNumChannels_ = -1;
   int outNumChannels_ = -1;
 
   const torch::Tensor samples_;