Fix `routing.get_name()` not to assume all routines have `__name__` (#2648)

Fix `routing.get_name()` not to assume all routines have `__name__` (#2648)

Fix `routing.get_name()` to use the `__name__` attribute only if it is
actually present, rather than assuming that all routine and class types
have it, and use the fallback to class name otherwise.  This is
necessary for `functools.partial()` that doesn't have a `__name__`
attribute, but is recognized as a routine starting with Python 3.13.0b3.
Since for older versions of Python, it would have used the fallback
anyway, this doesn't really change the behavior there.

Fixes #2638