Support constructing a Quantity from a NDData object

[Cadair]

What is the problem this feature will solve?

In [3]: c = NDData(np.zeros((10,10)), unit=u.count)

In [4]: u.Quantity(c)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[5], line 1
----> 1 u.Quantity(c)

File ~/.virtualenvs/sunpy-dev/lib/python3.11/site-packages/astropy/units/quantity.py:552, in Quantity.__new__(cls, value, unit, dtype, copy, order, subok, ndmin)
    548 # check that array contains numbers or long int objects
    549 if value.dtype.kind in "OSU" and not (
    550     value.dtype.kind == "O" and isinstance(value.item(0), numbers.Number)
    551 ):
--> 552     raise TypeError("The value must be a valid Python or Numpy numeric type.")
    554 # by default, cast any integer, boolean, etc., to float
    555 if float_default and value.dtype.kind in "iuO":

TypeError: The value must be a valid Python or Numpy numeric type.

Describe the desired outcome

a NDData object has a .unit and is "array like" I feel like this should work, and be equivalent to u.Quantity(c.data, unit=c.unit).

Additional context

No response

[neutrinoceros]

This feels like something that could be addressed in the Quantity 2.0 project. What do you think @nstarman ?

[nstarman]

I'm hoping that in Q2.0 we simplify the construction of Quantity, further optimizing it for speed. Like NumPy, Jax, etc have asarray we would then provide a quantity() function that munges all the various objects into a Quantity. So yes, this should be supported!