slow `predict_as_dataframe` function

[sevmag]

The function:

https://github.com/graphnet-team/graphnet/blob/401f28b450e995cc567a70e83bb813757e9a4d63/src/graphnet/models/easy_model.py#L323

Can be really slow when querying for additional attributes, which is handled here:

https://github.com/graphnet-team/graphnet/blob/401f28b450e995cc567a70e83bb813757e9a4d63/src/graphnet/models/easy_model.py#L381-L397

In the prediction loop, we are already looping through the whole data. Can we think of a way to utilise that initial loop already to get additional attributes without looping through the dataloader again? I think the least we can do is put a progress bar in the second loop to let the user know that the program hasn't stalled (I was very confused at times, why does it take so long.?).