Revert "[SPARK-38297][PYTHON] Explicitly cast the return value at Dat…

…aFrame.to_numpy in POS"

This reverts commit a0d2be5.

python/pyspark/pandas/generic.py

@@ -573,7 +573,7 @@ def to_numpy(self) -> np.ndarray:
         >>> ps.Series(['a', 'b', 'a']).to_numpy()
         array(['a', 'b', 'a'], dtype=object)
         """
-        return cast(np.ndarray, self._to_pandas().values)
+        return self.to_pandas().values
 
     @property
     def values(self) -> np.ndarray: