add capability to interrupt the pipeline

[machineminded]

This PR adds the ability to interrupt the pipeline by passing a callback_on_step_end argument per documentation here:

https://huggingface.co/docs/diffusers/en/using-diffusers/callback#interrupt-the-diffusion-process

The example usage provided in the URL above should work as it is what I am using in Fooocus:

https://github.com/machineminded/Fooocus-inswapper/blob/main/modules/pm.py#L22 https://github.com/machineminded/Fooocus-inswapper/blob/main/modules/pm.py#L131

[Paper99]

Thanks for your great work! We've merged your PR.