test/e2e/upgrade: Raise default update-ack timeout to 10m

It's failing in [1]'s client-go bump to Kube 1.35, with timelines like
[2]:

* 11:17:27, test-suite patches ClusterVersion to request the update.
* 11:17:27, CVO Events UpgradeStarted (although it hasn't actually pivoted the target yet, might want to adjust this Event name/timing) and RetrievePayload: Retrieving and verifying payload…
* 11:17:28, CVO creates version–fgn9s.
* 11:17:28, CVO starts watching version--fgn9s.
* 11:17:33, version--fgn9s container started.  So it's not slow image pulls.
* 11:17:34, version--fgn9s container started again?  Not clear what happened here.
* 11:17:37, rename-to-final-location container started (the last container in version-... Pods, it should be an atomic, single-filesystem mv).
* 11:17:38, rename-to-final-location exits 0, so success, but the CVO does not notice.
* 11:19:27, test-case times out after 2m.
* 11:21:27, CVO refreshes the watch on version--fgn9s.

and CVO logs like:

  I0320 11:17:58.306414       1 reflector.go:1159] "Warning: event bookmark expired" err="k8s.io/client-go/tools/watch/informerwatcher.go:162: hasn't received required bookmark event marking the end of initial events stream, received last event 18.795159461s ago"
  I0320 11:18:08.306345       1 reflector.go:1159] "Warning: event bookmark expired" err="k8s.io/client-go/tools/watch/informerwatcher.go:162: hasn't received required bookmark event marking the end of initial events stream, received last event 28.795076029s ago"
  ...
  I0320 11:21:18.307818       1 reflector.go:1159] "Warning: event bookmark expired" err="k8s.io/client-go/tools/watch/informerwatcher.go:162: hasn't received required bookmark event marking the end of initial events stream, received last event 3m38.796537922s ago"
  I0320 11:21:27.596115       1 trace.go:236] Trace[23813503]: "Reflector WatchList" name:k8s.io/client-go/tools/watch/informerwatcher.go:162 (20-Mar-2026 11:17:28.301) (total time: 239294ms):

21 - 17 = 4m, and I'm giving it 10m to be safe.  The bump allows work
like [1] to move forward while we troubleshoot the client issue.
We'll definitely want to revert this once the 1.35 clients are fixed.

[1]: openshift/cluster-version-operator#1282
[2]: https://prow.ci.openshift.org/view/gs/test-platform-results/pr-logs/pull/openshift_cluster-version-operator/1282/pull-ci-openshift-cluster-version-operator-main-e2e-agnostic-ovn-upgrade-out-of-change/2034935978228977664

Author: wking

test/e2e/upgrade/upgrade.go

@@ -82,7 +82,7 @@ var (
 // upgradeAbortAtRandom is a special value indicating the abort should happen at a random percentage
 // between (0,100].
 const upgradeAbortAtRandom = -1
-const defaultCVOUpdateAckTimeout = 2 * time.Minute
+const defaultCVOUpdateAckTimeout = 10 * time.Minute
 
 // SetTests controls the list of tests to run during an upgrade. See AllTests for the supported
 // suite.