Fix data type incompatible

Author: halogen22

pandas/core/arrays/base.py

@@ -2513,7 +2513,7 @@ def _mode(self, dropna: bool = True) -> Self:
         # error: Incompatible return value type (got "Union[ExtensionArray,
         # Tuple[np.ndarray, npt.NDArray[np.bool_]]", expected "Self")
         result, _ = mode(self, dropna=dropna)
-        return result
+        return result  # type: ignore[return-value]
 
     def __array_ufunc__(self, ufunc: np.ufunc, method: str, *inputs, **kwargs):
         if any(