ci: fix environment configuration on Ubuntu 24.04 arm64

[galargh]

This fixes the environment configuration on Ubuntu 24.04 arm64 machines.

The context for the fix is that Ubuntu 24.04 comes with glibc 2.39 installed. Using older versions of nvcc with that glibc version results in the following errors - https://bugs.launchpad.net/ubuntu/+source/mumax3/+bug/2032624. This is specific to arm64 builds only.

On the plus side, we no longer have to downgrade gcc.

As a follow-up piece of work, we should consider installing the latest version of CUDA toolkit in the AMIs.

TODO (@galargh):

• upgrade 4xlarge self-hosted runners to Ubuntu 24.04

[BigLep]

@rjan90 : are you able to take this one?

[rjan90]

@galargh Regarding the missing TODO item about upgrading 4xlarge self-hosted runners to Ubuntu 24.04, do you think this should be addressed before this PR is ready, or handled as a follow-up task?

I have also written up a issue ticket about the follow-up piece of work of installing the latest version of CUDA toolkit in the AMIs: #515

[galargh]

@galargh Regarding the missing TODO item about upgrading 4xlarge self-hosted runners to Ubuntu 24.04, do you think this should be addressed before this PR is ready, or handled as a follow-up task?

@rjan90 I'm ready to go with the upgrade at any moment. I just wanted to first check with you if you're OK with the changes proposed in this PR. If so, I'm going to upgrade the runners and merge this PR.

[rjan90]

'm ready to go with the upgrade at any moment. I just wanted to first check with you if you're OK with the changes proposed in this PR. If so, I'm going to upgrade the runners and merge this PR.

Yeah, I´m good with it

[galargh]

I updated the runners earlier today and rerun the CI here to verify everything works as expected. I'm going to merge it now to keep the master branch 🟢