change to code for live preview fix on OSX to be bit more obvious

        with devices.autocast():

            p.init(p.all_prompts, p.all_seeds, p.all_subseeds)

            if shared.opts.live_previews_enable and sd_samplers.approximation_indexes.get(shared.opts.show_progress_type, 0) == 1:

                # preload approx nn model before sampling for a more deterministic result

            # for OSX, loading the model during sampling changes the generated picture, so it is loaded here

            if shared.opts.live_previews_enable and opts.show_progress_type == "Approx NN":

                sd_vae_approx.model()

            if not p.disable_extra_networks: