CPU Support Minor Bug

Hello, I believe I found a minor bug in `IntentAccuracyDailyDialog`, lines 672-3 in `envs/text_generation/metric.py`. The device is currently set with the following two lines:
```
self._device = "cuda" if torch.cuda.is_available() else "cpu"
self._device = f"cuda:{torch.cuda.device_count() - 1}"
```
However, I believe it should be such that the device is `f"cuda:{torch.cuda.device_count() - 1}"` if on GPU and `"cpu"` otherwise (as currently it can never be set to CPU, and instead tries to find `"cuda:-1"`). Thanks so much for putting this library together!