REGR: np.argwhere on pd.Series raises ValueError
- [ ] closes #35331 

not sure what behaviour we want (will add tests after discussion). We should be thinking of removing \_\_array_wrap__ in favour of \_\_array_ufunc__ and \_\_array_function__ anyhow.

from https://numpy.org/doc/stable/user/basics.subclassing.html?highlight=__array_wrap__#array-wrap-for-ufuncs-and-other-functions

> It is hoped to eventually deprecate these, but __array_wrap__ is also used by other numpy functions and methods, such as squeeze, so at the present time is still needed for full functionality.

in 0.25.3 we returned the NumPy array (albeit with a warning)

```
>>> pd.__version__
'0.25.3'
>>>
>>> s = pd.Series(np.random.randn(5), index=["a", "b", "c", "d", "e"])
>>> s
a    1.640847
b    0.316918
c   -0.193584
d    1.473205
e    0.357223
dtype: float64
>>>
>>> np.argwhere(s < 0)
C:\Users\simon\Anaconda3\lib\site-packages\numpy\core\fromnumeric.py:61: FutureWarning: Series.nonzero() is deprecated and will be removed in a
 future version.Use Series.to_numpy().nonzero() instead
  return bound(*args, **kwds)
array([[2]], dtype=int64)
>>>
```
