[Testing] Fix RL9 Nvidia driver issue due to RL9 new release

[LujieDuan]

Description

Rocky Linux 9.5 has been released Nov 19.

RL9's default repo setting (/etc/yum.repos.d/rocky.repo) uses mirrorlist (e.g., mirrorlist=https://mirrors.rockylinux.org/mirrorlist?arch=$basearch&repo=AppStream-$releasever$rltype) to fetch packages, and the mirrorlist will automatically use the RL9.5 repo even when the GCE image is still on 9.4.

This is fine for most packages, but CUDA requires the exact version of kernel-devel package (the version that match the OS kernel version). RL9.4's kernel-devel won't exist in RL9.5 repo.

Fix:

When GCE builds a new RL9.5 image, the driver issue will be resolved. To fix the issue right now and prevent it from happening again, add a new repo that matches the OS version.

Notes:

• Also removed a previous version pin and install the latest CUDA 12.6.3;
• We won't need to apply similar fix to RL8 since RL8.10 is already the last RL8.

Related issue

b/380251927

How has this been tested?

Integration tests passing.

Checklist:

• Unit tests
  • Unit tests do not apply.
  • Unit tests have been added/modified and passed for this PR.
• Integration tests
  • Integration tests do not apply.
  • Integration tests have been added/modified and passed for this PR.
• Documentation
  • This PR introduces no user visible changes.
  • This PR introduces user visible changes and the corresponding documentation change has been made.
• Minor version bump
  • This PR introduces no new features.
  • This PR introduces new features, and there is a separate PR to bump the minor version since the last release already.
  • This PR bumps the version.

[LujieDuan]

The mentioned issue has been fixed in the new version of CUDA, so here we can simplify the steps to install CUDA+driver from one single package.