Make ClassLabel1DModality average out intermediate dims
Make ClassLabel1DModality average out intermediate dims

PiperOrigin-RevId: 175244191

tensorflow/tensor2tensor,tensorflow/tensor2tensor,rsepassi/tensor2tensor,vthorsteinsson/tensor2tensor,rsepassi/tensor2tensor,rsepassi/tensor2tensor,vthorsteinsson/tensor2tensor,vthorsteinsson/tensor2tensor,vthorsteinsson/tensor2tensor,rsepassi/tensor2tensor,tensorflow/tensor2tensor,tensorflow/tensor2tensor,tensorflow/tensor2tensor