`run_mlm.py` doesn't log perplexity to `wandb`
Author: david-waterworth
Pull request: no

### System Info

When I run `run_mlm.py`  all of the metrics which are created with names such as `train_loss` or `eval_loss` are logged to `wandb` reformatted as `train/loss` or `eval/loss`. However the eval perplexity is simply logged as `perplexity` and is not included in the wandb metrics

https://github.com/huggingface/transformers/blob/3658488ff77ff8d45101293e749263acf437f4d5/examples/pytorch/language-modeling/run_mlm.py#LL620C1-L635C46

The following is the output from `run_mlm.py`, you can observe that only metrics with a `eval_` prefix are included. I couldn't find in the code where the wandb login integration is or I'd dig further.

``` console
***** eval metrics *****
  epoch                   =       10.0
  eval_accuracy           =     0.9946
  eval_loss               =     0.0248
  eval_runtime            = 0:10:43.84
  eval_samples            =      62679
  eval_samples_per_second =     97.351
  eval_steps_per_second   =      3.043
  perplexity              =     1.0251
wandb: Waiting for W&B process to finish... (success).
wandb: / 0.130 MB of 0.130 MB uploaded (0.000 MB deduped)
wandb: Run history:
wandb:                  eval/accuracy ▁
wandb:                      eval/loss ▁
wandb:                   eval/runtime ▁
wandb:        eval/samples_per_second ▁
wandb:          eval/steps_per_second ▁
wandb:                    train/epoch ▁▂▂▃▃▄▄▅▅▆▆▇▇███
wandb:              train/global_step ▁▂▂▃▃▄▄▅▅▆▆▇▇███
wandb:            train/learning_rate █▇▇▆▆▅▅▄▄▃▃▂▂▁
wandb:                     train/loss █▇▆▅▅▄▃▃▂▂▂▂▁▁
wandb:               train/total_flos ▁
wandb:               train/train_loss ▁
wandb:            train/train_runtime ▁
wandb: train/train_samples_per_second ▁
wandb:   train/train_steps_per_second ▁
wandb: 
wandb: Run summary:
wandb:                  eval/accuracy 0.99464
wandb:                      eval/loss 0.02479
wandb:                   eval/runtime 643.8475
wandb:        eval/samples_per_second 97.351
wandb:          eval/steps_per_second 3.043
wandb:                    train/epoch 10.0
wandb:              train/global_step 16540
wandb:            train/learning_rate 0.0
wandb:                     train/loss 0.0568
wandb:               train/total_flos 3.677755155323775e+18
wandb:               train/train_loss 0.02581
wandb:            train/train_runtime 87644.5711
wandb: train/train_samples_per_second 144.98
wandb:   train/train_steps_per_second 0.189
```
I'm also not getting per-epoch eval metrics logged to wandb but I may have omitted a cmd line parameter.

### Who can help?

_No response_

### Information

- [X] The official example scripts
- [ ] My own modified scripts

### Tasks

- [X] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [ ] My own task or dataset (give details below)

### Reproduction

Run train_mlm with wandb enabled

### Expected behavior

Log `eval/perpleixity` to `wandb`

Comments:
Hi @david-waterworth, thanks for raising this issue. 

There's isn't an `eval_` prefix in front if the perplexity metric because it's not part of the key [when added to the metrics dictionary](https://github.com/huggingface/transformers/blob/2faa09530bc5d29756bddfec12037c066cc85a02/examples/pytorch/language-modeling/run_mlm.py#LL632C19-L632C19). Would you like to open a PR to update this? 

Regarding wandb logging, the integration logic can be [found here](https://github.com/huggingface/transformers/blob/867316670a909dd1a60ad69cdb0c962bdc6f0cd4/src/transformers/integrations.py#L663). These are community contributed and not actively maintained by hugging face. Feel free to open a PR if there's an issue you've spotted in the logging or ping the original contributors of the callback. 

This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.