upgrade/upgrades: TestSetUiDefaultTimezone failed

upgrade/upgrades.TestSetUiDefaultTimezone [failed](https://mesolite.cluster.engflow.com/invocations/default/9737b54f-533d-4d72-88c3-4a84eef9d1c6?testReportRun=8&testReportShard=4&testReportAttempt=1#targets-Ly9wa2cvdXBncmFkZS91cGdyYWRlczp1cGdyYWRlc190ZXN0) on release-25.2 @ [2b1c44f21770bbfd03b27a0eb7eec86296a052d2](https://github.com/cockroachdb/cockroach/commits/2b1c44f21770bbfd03b27a0eb7eec86296a052d2):

```
=== RUN TestSetUiDefaultTimezone
test_log_scope.go:165: test logs captured to: outputs.zip/logTestSetUiDefaultTimezone20593992
test_log_scope.go:76: use -show-logs to present logs inline
v25_2_set_ui_default_timezone_test.go:88: -- test log scope end --
test logs left over in: outputs.zip/logTestSetUiDefaultTimezone20593992
--- FAIL: TestSetUiDefaultTimezone (48.37s)
=== RUN TestSetUiDefaultTimezone/display_timezone=Etc/UTC
test_server_shim.go:141: cluster virtualization disabled in global scope due to issue: #76378 (expected label: C-bug)
v25_2_set_ui_default_timezone_test.go:61: condition failed to evaluate within 45s: from v25_2_set_ui_default_timezone_test.go:64: expected ui.default_timezone to be set to Etc/UTC, got
--- FAIL: TestSetUiDefaultTimezone/display_timezone=Etc/UTC (46.19s)
```

Parameters:
- attempt=1
- run=8
- shard=4
Help

See also: [How To Investigate a Go Test Failure \(internal\)](https://cockroachlabs.atlassian.net/l/c/HgfXfJgM)

/cc @cockroachlabs/release-eng @cockroachlabs/release-eng

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Jira issue: CRDB-66357

Start with TestSetUiDefaultTimezone in v25_2_set_ui_default_timezone_test.go and reproduce the failure at commit 2b1c44f21770bbfd03b27a0eb7eec86296a052d2. Inspect the captured test logs from outputs.zip/logTestSetUiDefaultTimezone20593992 and the failing condition around line 64. Done means the test observes ui.default_timezone set to Etc/UTC.

Written by the indexing model from the issue text.