update CI to use gcc-14

[dynst]

Is your feature request related to a problem? Please describe.

Currently CI is limited to treating gcc-12 as the newest, because it's the newest available on ubuntu-22.04.

ubuntu-24.04 had mysterious time outs in CI when trying to run a GCC build on it in February https://github.com/CleverRaven/Cataclysm-DDA/pull/79517#issuecomment-2641765174

But the clang++ 18 build is already running on ubuntu-24.04, and it also enables ASan with sanitize: address, and it's working fine.

Solution you would like.

Update the runners to ubuntu-24.04 and the latest GCC after the slowness is resolved.

GitHub Actions run on Microsoft Azure, and there's a CPU quota bug known and fixed upstream https://github.com/Azure/WALinuxAgent/issues/3355 but that hasn't been released yet, so that may be related to making the build job slow.

Microsoft Azure Linux Agent v2.14.0.1 hasn't been deployed yet.

Describe alternatives you have considered.

Waiting to deal with it until April 2027 when ubuntu-22.04 runner images are also removed.

Additional context

#80524

Testing with g++-14 may help with users like #78138