Incorrect padding for get_seq_len of features.py
https://github.com/NVIDIA/NeMo/blob/4d78737f612964ff9cce2120bb28ec94f874ab07/nemo/collections/asr/parts/preprocessing/features.py#L392C1-L392C32

I don't know what was intended here, but to me it's clear there is redundency or error, because `self.n_fft // 2 * 2` is the same as just `self.n_fft`. Perhaps it was intended to be the power of two (aka `2 ** 2`)?
```
# Assuming that center is True is stft_pad_amount = 0
pad_amount = self.stft_pad_amount * 2 if self.stft_pad_amount is not None else self.n_fft // 2 * 2
```
What was the intended purpose of the line? Perhaps we want n_fft to be even?

