Tests relying on Chromium do not pass on Ubuntu 24+

[frankieroberto]

The visual regression tests, and some of the unit tests, fail when being run by GitHub on the latest version (v24) of Ubuntu, with the following error:

Failed to launch the browser process!
[2459:2459:0114/164343.195445:FATAL:zygote_host_impl_linux.cc(126)] No usable sandbox! Update your kernel or see https://chromium.googlesource.com/chromium/src/+/main/docs/linux/suid_sandbox_development.md for more information on developing with the SUID sandbox. If you want to live dangerously and need an immediate workaround, you can try using --no-sandbox.
[0114/164343.206985:ERROR:file_io_posix.cc(145)] open /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq: No such file or directory (2)
[0114/164343.207179:ERROR:file_io_posix.cc(145)] open /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq: No such file or directory (2)

TROUBLESHOOTING: https://pptr.dev/troubleshooting

at ChildProcess.onClose (node_modules/@puppeteer/browsers/src/launch.ts:436:11)

See https://github.com/nhsuk/nhsuk-frontend/actions/runs/12772313119/job/35601543879 for the full logs