fix SmartRelationshipsMixin to override exclude metadata

src/utils_flask_sqla/schema.py

@@ -72,4 +72,5 @@ def __init__(self, *args, **kwargs):
             kwargs["only"] = only
         if exclude:
             kwargs["exclude"] = exclude
+            self.opts.exclude = set(self.opts.exclude).difference(only)
         super().__init__(*args, **kwargs)