Automatic merge from submit-queue (batch tested with PRs 57533, 57524). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
periodically check whether assigned kubelet config should become last-known-good
Fixes#57808
Previously, the last-known-good was only updated on Kubelet restart. This has been on my todo list for a while, good to finally have a PR up.
Previously we could have this scenario, which is fixed by this PR:
- lkg is set to local
- we set config A
- config A passes trial period, but nothing caused Kubelet to restart
- we set config B, which turns out to be invalid
- Kubelet will fall back to local, because lkg was never updated
```release-note
NONE
```
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