Updating feature set properties casing based on change in service (Azure#29481)

Author: maykumar-msft

sdk/ml/azure-ai-ml/azure/ai/ml/operations/_feature_set_operations.py

@@ -171,8 +171,8 @@ def begin_create_or_update(self, featureset: _FeatureSet) -> LROPoller[_FeatureS
         """
 
         featureset_spec = validate_and_get_feature_set_spec(featureset)
-        featureset.properties["featureset_properties_version"] = "1"
-        featureset.properties["featureset_properties"] = json.dumps(featureset_spec._to_dict())
+        featureset.properties["featuresetPropertiesVersion"] = "1"
+        featureset.properties["featuresetProperties"] = json.dumps(featureset_spec._to_dict())
 
         sas_uri = None
         featureset, _ = _check_and_upload_path(