Update model_index.json

Uses the config from https://huggingface.co/stabilityai/stable-diffusion-xl-base-1.0/blob/main/model_index.json now but with the pony scheduler

model_index.json

@@ -1,15 +1,8 @@
 {
   "_class_name": "StableDiffusionXLPipeline",
   "_diffusers_version": "0.36.0.dev0",
-  "feature_extractor": [
-    null,
-    null
-  ],
   "force_zeros_for_empty_prompt": true,
-  "image_encoder": [
-    null,
-    null
-  ],
+  "add_watermarker": null,
   "scheduler": [
     "diffusers",
     "EulerAncestralDiscreteScheduler"