thread leak in test: django dev server

# Thread leak: Django Dev Server 📋 **Complete fix guidance**: [How-To: Thread Leaks](How-To-Thread-Leaks.md) The django "dev server" is starting during test but not being cleaned up. ## Reproduction To reproduce the thread leak: 1. Remove the `@thread_leak_allowlist` decorator from the test if present 2. Run: ```bash export SENTRY_THREAD_LEAK_STRICT=1 pytest -v tests/acceptance/test_disabled_custom_symbol_sources.py::DisabledCustomSymbolSourcesSettingsTest::test_disabled_custom_symbol_sources ``` ## Example Thread Leaks ``` <Thread(Thread-112 (process_request_thread), started daemon 140571863676608)>@django.core.servers.basehttp.ThreadedWSGIServer.process_request_thread ``` ## Verify Fix Remove any `@thread_leak_allowlist` decorators and confirm no failures: ```bash export SENTRY_THREAD_LEAK_STRICT=1 pytest -v tests/acceptance/test_disabled_custom_symbol_sources.py ``` ## Impact - Tests: 295 - Files: <Many>