Fix tests in preparation for behavior change in modern Cython

[bmeagherix]

Modern cython changes how cpdef enums are exposed. Update the tests so that they will work with both old and new cython.

Given

    cpdef enum iscsi_session_type:
        ISCSI_SESSION_DISCOVERY
        ISCSI_SESSION_NORMAL

We used to be able to either use iscsi.ISCSI_SESSION_NORMAL or iscsi.iscsi_session_type.ISCSI_SESSION_NORMAL. With modern cython, only the latter works.

From https://cython.readthedocs.io/en/latest/src/userguide/language_basics.html#structs-unions-enums

Up to Cython version 3.0.x, this used to copy all item names into the global module namespace, so that they were available both as attributes of the Python enum type (CheseState above) and as global constants. This was changed in Cython 3.1 to distinguish between anonymous cpdef enums, which only create global Python constants for their items, and named cpdef enums, where the items live only in the namespace of the enum type and do not create global Python constants.

Verified the breakage and fix in a venv on Debian Trixie nightly, and on Bookworm.

The https://pypi.org/project/Cython/ shows

• 3.1.0 (2025-05-08)

[rosjat]

@Flameeyes can you review and merge on approval please

[rosjat]

@Flameeyes i will merge this now since it simply bumps the precommit and changes a test case