Notebook smoke test failures (2026-04-01)

The following notebooks failed during the quarterly smoke test:

- `collaborative/DFU/station_hourly_profiles.ipynb`
- `collaborative/IOU/8760/one_in_x_in_8760.ipynb`
- `collaborative/IOU/vulnerability_assessment/vulnerability_assessment.ipynb`

See the [workflow run](https://github.com/cal-adapt/cae-notebooks/actions/runs/23843034295) for details.