[BUG]: __getattr__ and base class order

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Problem description

In the binding code below __getattr__ will only be found in the derived class if we do:
py::class_<Derived, Base, OtherBase>(m, "Derived")
if we instead do:
py::class_<Derived, OtherBase, Base>(m, "Derived")
note the order of the base classes switched,
the bound __getattr__ will never be called.

From what I understand from the documentation (https://pybind11.readthedocs.io/en/latest/advanced/classes.html#multiple-inheritance) the order of the base classes should not matter?

This is tested with the latest master as of writing.

Reproducible example code

// binding code
#include <pybind11/pybind11.h>

namespace py = pybind11;

struct Base {
    virtual ~Base() = default;
    int base() const { return 0; }
};
struct OtherBase {
    int other() const { return 3; }
};
struct Derived : Base, OtherBase{
    int id() const { return 2; }
};

PYBIND11_MODULE(bar, m) {
    py::class_<Base>(m, "Base")
        .def(py::init<>())
        .def("base", &Base::base)
        .def("__getattr__", [](Base&, std::string key) {
            return "Base GetAttr: " + key;
        });

    py::class_<OtherBase>(m, "OtherBase")
        .def("other", &OtherBase::other);

    py::class_<Derived, OtherBase, Base>(m, "Derived")
        .def(py::init<>())
        .def("id", &Derived::id);
}

// test code
import bar

d = bar.Derived()
print(f"d.base(): {d.base()}")
print(f"d.other(): {d.other()}")
print(f"d.id(): {d.id()}")
print(f"d.prop: {d.prop}") # this will fail (if Base is not the first base class)

Start with the provided C++ binding and Python reproduction, and read the linked pybind11 multiple-inheritance documentation first. Confirm behavior for both base-class orders and trace the relevant class-binding and attribute-lookup entry point; done means getattr behaves consistently regardless of base order, with regression coverage for the reproduction.