Addressing a training quick from earlier SimpleTuner versions

Update model_index.json

v1: 38800 + 21800 + 15400 steps of mixed LAION/MJ dataset and offset noise with input perturbation on a probability of 25%, 10% caption dropout, cosine LR 4e-7 to 8e-7 every 3200 steps, no min-snr loss augmentation