UI: Loss vs. Steps plot during training

[Jurph]

While training embeddings, the current value for Loss is displayed and the current value for Step is displayed, but without context it is hard to understand/evaluate whether training is going well. (I think the Loss function in this case also isn't terribly useful, but that's a separate discussion!) Perhaps we could get a more intuitive feel for the progress of a training run if those scalars were replaced with a gradio.Plot() element?