Update GitHub actions and Netlify build to run `ubuntu-24.04`

[romaricpascal]

What

Update GitHub actions to run ubuntu-24.04 rather than ubuntu-22.04, fixing any issue encountered on the way.
Once done, update Netlify's build image to use ubuntu-20.04 as well.

Important

We want to use ubuntu-24.04 rather than ubuntu-latest so we're in control of when we upgrade to a newer version
rather than that being dictated by GitHub updates

Why

To upgrade from the deprecated Ubuntu 20.04 environment on Netlify, and more generally to keep running on the most up to date environment.

Who needs to work on this

Developers

Who needs to review this

Developers

Done when

• GitHub actions run on ubuntu-24.04
• Netlify builds use ubuntu-24.04 as well.