fix: remove duplicate --use-latest pytest option in spin conftest

[odncode]

Summary

Remove duplicate --use-latest pytest option registration that prevents the unit test suite from collecting.

Problem

Running pytest test/unit/ fails during collection with:

ValueError: option names {'--use-latest'} already added

--use-latest is registered in both test/unit/conftest.py (added in #3040) and test/unit/spin/conftest.py (from #2506). pytest raises on the duplicate.

Fix

Remove pytest_addoption from test/unit/spin/conftest.py. The root test/unit/conftest.py already registers the option and it applies to all subdirectories.

Testing

State	Result
Before	pytest test/unit/ fails with collection error
After	468 passed, 1 failed, 19 skipped, 21 errors

Note: The 1 failure (complex_dag) and 21 errors (secrets/system_context tests) are pre-existing infrastructure issues unrelated to this change.

[greptile-apps]

Greptile Summary

Removes a duplicate pytest_addoption hook from test/unit/spin/conftest.py that re-registered --use-latest, causing pytest collection to abort with a ValueError when running the full test/unit/ suite.

• The root test/unit/conftest.py (added in Testing Infra Enhancements #3040) already registers --use-latest and pytest propagates it to all subdirectories, making the spin-level registration redundant and conflicting.
• spin/conftest.py still calls request.config.getoption(\"--use-latest\", default=False) as before, which continues to work because the option is now registered exactly once at the correct scope.

Confidence Score: 5/5

Safe to merge — removes a single duplicate option registration that was breaking test collection; no logic changes.

The change is a one-hunk deletion of eight lines. The root conftest already owns the --use-latest registration, and the spin fixtures continue to consume it via request.config.getoption without any modification.

No files require special attention.

Important Files Changed

Filename	Overview
test/unit/spin/conftest.py	Removes duplicate pytest_addoption that registered --use-latest twice; the root test/unit/conftest.py already owns the registration, so spin tests pick it up automatically.

_{Reviews (1): Last reviewed commit: "fix: remove duplicate --use-latest pytes..." | Re-trigger Greptile}