Fix red develop 58445d2ed7b0

The merge lane found `develop` red at `58445d2ed7b05f5f998f5d65a0680ffb46e3b170` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `tests/test_trigger_user_registered.py::test_an_accepted_invitation_reaches_the_inviting_orgs_trigger_once` - `api-unit-dc-test` The whole gate log: artifact `14651` on lane task 12920. 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.

No code needed: the red was a one-off xdist worker crash (gw5 killed, no traceback or timeout dump), not a test failure. It does not reproduce on develop e7ceb65: the file passes 33/33 and the full API suite at -n 9 passes the target test. Filed draft #12944 for an unrelated siem_export flake. Memory: none applied.