Replace any with uninferable when returning values from numpy t…

…ransform

Turns out that this was conflicting with the `any` builtin, while the original
intention was to return a value that cannot be inferred, until we have support
for types.

This should fix a couple of false positives on pylint's side where the return
value of numpy functions was considered to be itself a function.

Close pylint-dev/pylint#2784