Update code generation scripts with k8s v1.30 libraries

[mtardy]

Maybe (if we continue upgrading k8s deps along Cilium) during Cilium v1.16 dep update.

Commit https://github.com/cilium/tetragon/commit/a9c509f1f7c738bbeb1565f83eb9da70941a22ba replaced execution of deprecated scripts with k8s.io/code-generator/kube_codegen.sh. However, kube_codegen.sh doesn't generate code on its own, but rather defines helper functions. To migrate to kube_codegen.sh we'll need to call these functions from another script. Additionally, it'll change with version 1.30 of k8s libraries - that's why I opted to simply revert the change for now. When k8s libraries are updated to 1.30, the code generation scripts should be updated too.

_Originally posted by @lambdanis in https://github.com/cilium/tetragon/issues/2339

[lambdanis]

Just for reference, PR adding k8s 1.30 support to Cilium: https://github.com/cilium/cilium/pull/31687 Tetragon will need similar changes in the code generation scripts.