AT2 CI Build Version Upgrade -- CUDA 11->12

[sebrowne]

The current required cuda11 GitHub Action check has been set to non-required and the cuda12 check has been set to required.

Many weeks of runs have demonstrated the cuda12 job to be reliable.

This change was intended to be scheduled and deployed with advance notice, but an internal error relating to the cuda11 check was blocking Pull Requests, and thus it was decided to deploy this change ASAP.

If you encounter any issues that you think are related to this change, please open an issue and tag @trilinos/framework.

[sebrowne]

Transition completed