Update pipeline_controlnet_sd_xl_img2img.py (#7353)

* Update pipeline_controlnet_sd_xl_img2img.py

fix: safetensors load error

* fix for pass test

---------
Co-authored-by: YiYi Xu <yixu310@gmail.com>

src/diffusers/pipelines/controlnet/pipeline_controlnet_sd_xl_img2img.py

@@ -32,6 +32,7 @@ from diffusers.utils.import_utils import is_invisible_watermark_available
 
 from ...image_processor import PipelineImageInput, VaeImageProcessor
 from ...loaders import (
+    FromSingleFileMixin,
     IPAdapterMixin,
     StableDiffusionXLLoraLoaderMixin,
     TextualInversionLoaderMixin,
@@ -161,6 +162,7 @@ class StableDiffusionXLControlNetImg2ImgPipeline(
     StableDiffusionMixin,
     TextualInversionLoaderMixin,
     StableDiffusionXLLoraLoaderMixin,
+    FromSingleFileMixin,
     IPAdapterMixin,
 ):
     r"""