Update preprocessor_config.json

`transformers` has used `Qwen2VLImageProcessor` as Qwen2.5-VL's image processor. We need to update accordingly (see https://github.com/huggingface/transformers/pull/36164#issuecomment-2658902781)

preprocessor_config.json

@@ -14,6 +14,6 @@
     0.26130258,
     0.27577711
   ],
-  "image_processor_type": "Qwen2_5_VLImageProcessor",
+  "image_processor_type": "Qwen2VLImageProcessor",
   "processor_class": "Qwen2_5_VLProcessor"
 }