__is_const_callable_object_v does not work for objects with multiple overloads

[danhoeflinger]

The way in which __is_const_callable_object_v is implemented does not work when there are multiple overloads of operator() (even in the form of templates).

It is only used in one place, replace_copy_if. It seems it could be replaced by a check to is_invocable_v with the specific argument type we are interested in, and then removed from utils. We need to check that we don't have unintended consequences on replace_copy_if though.