during migration do not overwrite symlinks

invokeai/backend/config/model_install_backend.py

@@ -270,7 +270,6 @@ def _download_diffusion_weights(
             path = download_from_hf(
                 model_class,
                 repo_id,
-                cache_subdir="diffusers",
                 safety_checker=None,
                 **extra_args,
             )

invokeai/backend/model_management/model_manager.py

@@ -955,7 +955,9 @@ class ModelManager(object):
                 continue
             print(f"** {source} => {dest}")
             if source.exists():
-                if dest.exists():
+                if dest.is_symlink():
+                    print(f"** Found symlink at {dest.name}. Not migrating.")
+                elif dest.exists():
                     rmtree(source)
                 else:
                     move(source, dest)