Support v-prediction checkpoint models when set in the model manager

[dunkeroni]

Summary

Capture prediction type from model settings and pass it to the scheduler to enable v_prediction checkpoints to work again.

Related Issues / Discussions

I'm certain there is a more correct way to handle this in the model manager that would also allow automatic detection from checkpoint files, but this at least gets vpred models working again before we go make sweeping changes to the model probe code.

Since our conversion code does not check the settings on the checkpoint, attempting to convert a v_prediction model to Diffusers will still default over to epsilon prediction and it will forever fail afterwards. It is not currently possible for users to change a diffusers model to v_prediction in Invoke without editing the local json files. User Mewt on discord has found that huggingface repos with correct scheduler_config.json are able to work without issues, but I have found others online that still specify epsilon.

Closes #7495

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