adding `callback_on_step_end` for `StableDiffusionLDM3DPipeline`

[yiyixuxu]

Just realize the StableDiffusionLDM3DPipeline is still not using the new callback API
https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/stable_diffusion_ldm3d/pipeline_stable_diffusion_ldm3d.py

Is anyone interested in refactoring it? you can use this PR as a reference
#5812

[rootonchair]

Hi @yiyixuxu . Can I take this?

[yiyixuxu]

@rootonchair sure!