Fixing bugs in calling method ctc_decoder_predictions_tensor.
# What does this PR do ?

Fixed a bug in calling the ctc_decoder_predictions_tensor method from the WER objects instead of WER.decoding.

# Changelog 
- Changed all the wer.ctc_decoder_predictions_tensor to wer.decoding.ctc_decoder_predictions_tensor .

**PR Type**:
- [ ] New Feature
- [x ] Bugfix
- [ ] Documentation

