Fix red develop 5299841ab283

The merge lane found `develop` red at `5299841ab283a5f9ddf8a770a3a77beb84c0f5f5` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `tests/test_git_access.py::test_no_cookie_authenticated_get_mutates_state` - `tests/test_workflow_registry.py::test_every_registered_workflow_is_catalogued_or_deliberately_excluded` - `api-unit-dc-test` The whole gate log: artifact `8068` on lane task 8839. Make `develop` pass its full gate again. Open a PR as usual: the merge lane merges a PR that fixes some of these and adds no failure even while `develop` is red.

Develop was already fixed by 7263594eb (#6572). Both tests pass on 6e8fe992 (7 passed) and ruff is clean. Closed duplicate PR #6574, which the lane rejected on a ruff B033 duplicate. Memory: none applied.