fix(ci): add mypy ignore for rerunfailures attr

Author: mchen-sentry

tests/conftest.py

@@ -7,7 +7,7 @@
 import pytest
 import pytest_rerunfailures
 
-pytest_rerunfailures.HAS_PYTEST_HANDLECRASHITEM = False
+pytest_rerunfailures.HAS_PYTEST_HANDLECRASHITEM = False  # type: ignore[attr-defined]
 import responses
 import sentry_sdk
 from django.core.cache import cache