DEPR: remove get_values, SparseArray.values
The cleanups in libreduction are made possible by SparseArray.values going away.
I would have thought these changes would have been fine...just need to diagnose the CI failures. I think there is some JSON code that can get cleaned up as part of this:

https://github.com/pandas-dev/pandas/blob/ed20822a54e3863b393554ecca801654af105555/pandas/_libs/src/ujson/python/objToJSON.c#L216
 > I think there is some JSON code that can get cleaned up as part of this:

Nice.  Want me to do that here or save for follow-up? Up to you > > I think there is some JSON code that can get cleaned up as part of this:
>
> Nice. Want me to do that here or save for follow-up?

Let's do that here I would say, it's from the same PR that deprecated SparseArray.values: https://github.com/pandas-dev/pandas/pull/26421 (you are already removing part of the things of that PR that can be removed) removed examples from docstring, left the json since it wasnt obvious what to do in the places where is_sparse_array is currently called >  left the json since it wasnt obvious what to do in the places where is_sparse_array is currently called

From looking at my old PR, I think you can just remove the `is_sparse_array` where it is used (so change it back to how it was before that PR). SparseArray won't have a `values` attribute anymore, so that check will work fine now (and not trigger a warning).
 removed is_sparse_array, green Thanks @jbrockmendel 