How to remove `v_num` from the progress bar ?
Version: 0.7.3
The v_num is automatically added to progress_bar when some logger is used
It is not much a problem for tensorboard when v_num is just a simple number
But v_num for mlfow takes a lot of space
Traning step
def training_step(self, batch, batch_nb):
    ....
    log = { "trn_loss": 0.1, "lr": 0.001 }
    return {"loss": loss, "log": log, "progress_bar": log}

Progress bar when using with mlflow logger
 [00:33<00:46, 1.62s/it, loss=0.740, lr=8e-6, trn_loss=0.659, v_num=18_28bc973b1f0e42e8b4d664d1ef7812f6]

Also, loss is automatically added to progress_bar