Replace use of deprecated methods from Dandiset in dandi-schema p…

…ackage

dandiapi/api/services/version/metadata.py

@@ -43,4 +43,6 @@ def _normalize_version_metadata(
     }
     # Run the version_metadata through the pydantic model to automatically include any boilerplate
     # like the access or repository fields
-    return PydanticDandiset.unvalidated(**version_metadata).json_dict()
+    return PydanticDandiset.model_construct(
+        **version_metadata
+    ).model_dump(mode='json',exclude_none=True)