Remove incorrect and unused _Py_atomic_store_uint_release() method

[SubbaraoGarlapati]

_Py_atomic_store_uint_release() uses memory_order_relaxed when it should use memory_order_release. This method isn't used anywhere so instead of fixing it we can just delete it.

[python-cla-bot]

All commit authors signed the Contributor License Agreement.

[bedevere-app]

Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool.

If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.

[ZeroIntensity]

1. Please open a new PR for the main branch. We'll backport this to 3.14 using a bot. (Trying to switch branches will end up flooding codeowner inboxes.)
2. We keep the _Py_atomic APIs around for when we might need them -- it's fine if they're unused. Let's just fix the memory ordering.