[3.12] gh-111698: Restrict Py_mod_multiple_interpreters to 3.12+ Under Py_LIMITED_API (gh-111707) (gh-111787)

This should have been done in gh-104148.

(A similar fix has already be done for that slot's value macros, and backported to 3.12.  See gh-110968.)
(cherry picked from commit 836e0a75d565ecb7e2485fee88dbe67e649a1d5f)

Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>