Fix rank method with nullable int

Author: tqa236

pandas/core/arrays/masked.py

@@ -1058,7 +1058,7 @@ def factorize(
 
     @doc(ExtensionArray._values_for_argsort)
     def _values_for_argsort(self) -> np.ndarray:
-        return self._data
+        return self
 
     def value_counts(self, dropna: bool = True) -> Series:
         """