fix trellis pipeline

app.py

@@ -63,7 +63,11 @@ def end_session(req: gr.Request):
     shutil.rmtree(user_dir)
 
 def preprocess_image(image: Image.Image) -> Image.Image:
-    processed_image = _trellis_pipeline.preprocess_image(image)
+    trellis = get_trellis_pipeline()
+    if trellis is None:
+        # If the pipeline is not loaded, just return the original image
+        return image
+    processed_image = trellis.preprocess_image(image)
     return processed_image