check timestamps before waiting for agent rollout (backport #5698)

[mergify]

IMPORTANT: Please do not create a Pull Request without creating an issue first.

Problem:

PR attempts to address random upgrade fails where the upgrade fails due to the following error:

Wait for cluster settling down...
CAPI cluster fleet-local/local is provisioned (current generation: 838).
cluster.fleet.cattle.io/local patched
Error from server (NotFound): deployments.apps "fleet-agent" not found

This is caused by a delay in rollout of fleet-agent, where the rollout happens when the check for fleet-agent rollout status is running, and deployment gets recreated.

Solution:

The fix attempts to use original fleet-agent creation timestamp before fleet cluster object is patched, and ensures new fleet-agent deployment has a newer creation timestamp before rollout status is checked.

Related Issue:

Test plan:

---

This is an automatic backport of pull request #5698 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of cc1c2ad has failed:

On branch mergify/bp/v1.2/pr-5698
Your branch is up to date with 'origin/v1.2'.

You are currently cherry-picking commit cc1c2adb.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   package/upgrade/upgrade_manifests.sh

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[w13915984028]

Hit issue #5712 (comment), and need a further fix.

[w13915984028]

kubectl get deploy may fail because the above wait_for_deployment just success on the old deployment

with a fix on #5732