Prevent host uuid stomping for kubernetes agents

[rosstimothy]

#48012 recently converted the generation of host uuid files to prevent two processes from stomping on each other when trying to seed the host uuid of the process. However, that only addresses processes that write the host uuid file to disk. The Kubernetes agent no longer persists the host uuid on disk and instead stores it in a Kubernetes secret. The same optimistic locking should be applied to Kubernetes host uuids to prevent this class of bug entirely.