Fix static notebook export #9304
Description
The nbconvert cube.ipynb job is consuming a lot of CI time and then just timing out:
https://github.com/rerun-io/rerun/actions/runs/13890885895/job/38863029975
So it's disabled for now:
In general, nbconvert --to=html doesn't work at all right now. We should try to find a way to make it work.