Update supported k8s version wording

General MR

Summary

Updates wording to clarify BB's position on k8s version. Also updates to reference testing on 1.24 (release testing is on RKE2 1.24.4).

Preview of doc: https://repo1.dso.mil/platform-one/big-bang/bigbang/-/blob/k8s-version-docs/docs/prerequisites/kubernetes-preconfiguration.md#kubernetes-version