CLN: Remove unneeded check in BaseMaskedArray.sum (#52695)

CLN: Remove unneeded check

Author: topper-123

pandas/core/arrays/masked.py

@@ -1108,13 +1108,6 @@ def sum(
     ):
         nv.validate_sum((), kwargs)
 
-        # TODO: do this in validate_sum?
-        if "out" in kwargs:
-            # np.sum; test_floating_array_numpy_sum
-            if kwargs["out"] is not None:
-                raise NotImplementedError
-            kwargs.pop("out")
-
         result = masked_reductions.sum(
             self._data,
             self._mask,