[BUG]: Potential leaks when using enum_

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Problem description

Dear team, Asan reports possible memory leaks when wrapping enum from C++ (using py::enum_, precisely when a call to the value method is done.

Wrapping struct (using py::class_) seems to raise no leaks.

Config : python3.8 / gcc8.3, pybind v2.9.2

May be related to https://github.com/pybind/pybind11/issues/3228

Reproducible example code

#include <pybind11/pybind11.h>

enum Egg {
  Bar,
  Spam,  
};


namespace py = pybind11;

PYBIND11_MODULE(example, m) {
    py::enum_<Egg>(m, "Egg")
      .value("Bar", Egg::Bar)
      .value("Spam", Egg::Spam);
}

Start by reproducing the provided py::enum_ example with the reported Python and compiler configuration, then compare its memory behavior with the py::class_ case. Trace the .value() path and inspect the related issue #3228. Done means confirming the leak, identifying its ownership cause, and adding a regression test or documented result.