Add Kubernetes version 1.26 and set it to default for testing

[annajung]

Which issue is resolved by this Pull Request:
Part of #2450

Description of your changes:

• Move default KinD 1.25 to kind-cluster-1-25.yaml
• Add support for Kubernetes 1.26 and set it to default for testing
• Update the requirements.txt to run e2e with katib 0.15 and kfp 1.8.22

[annajung]

cc @kimwnasptd

[kimwnasptd]

@annajung I remember that we had to use the awk '!/well-defined/' command because of this bug in kustomize kubernetes-sigs/kustomize#5039.

Can we avoid these awk commands by instead using kustomize 5.0.1?

[annajung]

I think we can upgrade to kustomize 5.0.3

I ran a few tests to compare results between kustomize 5 with hack vs. kustomize 5.0.3 without the hack and looks like output is the same. I'll make a PR to upgrade Kustomize and update this PR.

[annajung]

This PR depends on kustomize 5.0.3 upgrade PR #2490, which fixes the kustomize 5 bug that makes the pipeline test fail.

[kimwnasptd]

All tests passed, nice one!

/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: annajung, kimwnasptd

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