containerd: default to 2.3.4 / runc 1.4.3 - #18683

Adds cos129 and cos129arm64, pinned to cos-129-19506-299-116, tested
against kops latest and 1.36. This follows the convention the other
recently added distros use: a new image is only exercised on the newer
kops branches.

At the same time, stop testing cos121 on kops latest and 1.36. kops
master now requires containerd 2.1.0 or newer (kubernetes/kops#18683),
while cos121 is pinned to containerd 2.0.7 because COS 121 cannot run
2.1+, so every cos121 job on kops latest fails at cluster creation:

  Error: spec.containerd.version: Invalid value: "2.0.7": unsupported
  legacy version; containerd 2.1.0 or newer is required

The 1.36 jobs still pass, since the release branch does not carry that
floor; dropping them as well is an age-out decision.

Note that dropping the newer branches requires passing None to
drop_unsupported_versions, because None is the entry that maps to
"latest kops" -- filtering only on version strings would have left
cos121 on latest, the broken combination, while removing the 1.36 jobs
that still work.

Also register the kops-distro-cos129 testgrid dashboard, in both the
dashboard group and the dashboard list, so the new jobs' annotations
resolve.

No kops changes are needed. ContainerOS is a single version-agnostic
distribution there: util/pkg/distributions/identify.go matches any "cos-"
prefix and DistributionContainerOS carries no version, so every COS
behavior in nodeup keys off that one constant.

Net effect is 78 job additions and 72 removals. The remaining line churn
in the generated files is cron reassignment for jobs whose position
shifted, not a change to those jobs.

Adds cos129 and cos129arm64, pinned to cos-129-19506-299-116, tested
against kops latest and 1.36. This follows the convention the other
recently added distros use: a new image is only exercised on the newer
kops branches.

At the same time, stop testing cos121 on kops latest and 1.36. kops
master now requires containerd 2.1.0 or newer (kubernetes/kops#18683),
while cos121 is pinned to containerd 2.0.7 because COS 121 cannot run
2.1+, so every cos121 job on kops latest fails at cluster creation:

  Error: spec.containerd.version: Invalid value: "2.0.7": unsupported
  legacy version; containerd 2.1.0 or newer is required

The 1.36 jobs still pass, since the release branch does not carry that
floor; dropping them as well is an age-out decision.

Note that dropping the newer branches requires passing None to
drop_unsupported_versions, because None is the entry that maps to
"latest kops" -- filtering only on version strings would have left
cos121 on latest, the broken combination, while removing the 1.36 jobs
that still work.

Also register the kops-distro-cos129 testgrid dashboard, in both the
dashboard group and the dashboard list, so the new jobs' annotations
resolve.

No kops changes are needed. ContainerOS is a single version-agnostic
distribution there: util/pkg/distributions/identify.go matches any "cos-"
prefix and DistributionContainerOS carries no version, so every COS
behavior in nodeup keys off that one constant.

Net effect is 78 job additions and 72 removals. The remaining line churn
in the generated files is cron reassignment for jobs whose position
shifted, not a change to those jobs.