refactor(diffusion): replace crop_shape with resize_shape and crop_ratio

[starlitxiling]

Summary / Motivation

When I used a larger resolution image with the diffusion policy, I found that the effect was not good. Later, I discovered that the diffusion policy strategy does not resize the image before cropping it, which causes problems when dealing with many images of different resolutions.

What changed

The image processing in the diffusion policy has been modified to resize the image before cropping it.

Checklist (required before merge)

• Linting/formatting run (pre-commit run -a)
• All tests pass locally (pytest)
• Documentation updated
• CI is green

[stefanwagnerdev]

I also assumed that resizing happens automatically.
PR looks good to me