make sure Soft Edge Detection has preprocessor applied

Author: Mary Hipp

invokeai/backend/model_manager/probe.py

@@ -485,6 +485,7 @@ def _scan_model(cls, model_name: str, checkpoint: Path) -> None:
     "lineart anime": "lineart_anime_image_processor",
     "lineart_anime": "lineart_anime_image_processor",
     "lineart": "lineart_image_processor",
+    "soft": "hed_image_processor",
     "softedge": "hed_image_processor",
     "hed": "hed_image_processor",
     "shuffle": "content_shuffle_image_processor",