Deprecating `Siglip2ImageProcessorFast`

[ariG23498]

The following lines trigger a deprecation warning for the Fast processor.

diffusers/src/diffusers/pipelines/z_image/pipeline_z_image_omni.py

Line 20 in 759164b

from transformers import AutoTokenizer, PreTrainedModel, Siglip2ImageProcessorFast, Siglip2VisionModel

diffusers/src/diffusers/pipelines/z_image/pipeline_z_image_omni.py

Line 156 in 759164b

siglip_processor: Siglip2ImageProcessorFast,

This is a quick fix and I could take it up if we are up for replacing the Processor with Siglip2ImageProcessor.

[DN6]

@ariG23498 Would you be able to handle the fix for this? Think everything would just work OOTB with your proposed change.