Upgrade to CKAN 2.10.9 patch

[thepsalmist]

The CKAN 2.10.9 patch release should be available from Wednesday 22/10/2025.
https://docs.ckan.org/en/latest/maintaining/releases.html

[kilemensi]

Anything keeping us on 2.10.x? Otherwise we should be planning a 2.11.x upgrade instead.