Increase code coverage across K3s

[dereknola]

Using this as a tracker for various PRs that relate to improving code coverage in 2025.
Here is a report from December 2024 of our current coverage.

Describe the solution you'd like
Code coverage goes up. We currently sit at 47.63% as of December 2024.

Describe alternatives you've considered

Additional context
We are hitting the ceiling of what is possible to track with code coverage metrics, as we have lots of

if err != nil { return err }

That count against our total coverage. However, we still have a few spots to could use increased coverage.