Fastconform SSL pretrained recipe failed potentially due to PTL 2.0
**Describe the bug**

the `examples/asr/speech_pretraining/speech_pre_training.py` is not working properly on the lates main branch, but working in 1.20. At first glance, the error could be related to the upgrade of Pytorch lightning 2.0.

**Error Brief**
```bash
lightning_fabric.utilities.exceptions.MisconfigurationException: `ModelCheckpoint(monitor='val_loss')` could not find the monitored key in the returned metrics: ['learning_rate', 'global_step', 'train_contrastive', 'train_backward_timing in s', 'train_step_timing in s', 'epoch', 'step']. HINT: Did you call `log('val_loss', value)` in the `LightningModule`?
```

**Error Details**

[error_logs.zip](https://github.com/NVIDIA/NeMo/files/12719689/error_logs.zip)



