Remove VAE encode

[vladmandic]

Describe the bug

Remote VAE encode was added via PR ##11017
I've added remote-vae feature for img2img and inpaint workflows for sd15, sdxl and flux.1

• sdxl: works for both img2img and inpaint
• sd15: works for img2img, but fails for inpaint
  • binary mask (typically a pil image type l) cannot be combined with image param if its a tensor
  • using remote vae to also encode mask image does work, but results in nonsense output as its not designed to encode binary masks
• flux: fails for img2img and inpaint
  • flux pipeline doesn't care if input image param is already encoded, it tries to encode it again

│ /home/vlado/dev/sdnext/venv/lib/python3.12/site-packages/diffusers/pipelines/flux/pipeline_flux_img2img.py:637 in prepare_latents
│    636 │   │   image = image.to(device=device, dtype=dtype)
│ ❱  637 │   │   image_latents = self._encode_vae_image(image=image, generator=generator)

Reproduction

(see above)

Logs

System Info

diffusers main branch commit 82188c

Who can help?

@hlky