release-26.2.1-rc: pkg/upgrade/upgrademanager/upgrademanager_test: TestMigrationFailure failed

pkg/upgrade/upgrademanager/upgrademanager_test.TestMigrationFailure [failed](https://mesolite.cluster.engflow.com/invocations/default/b9ba6621-b431-4f4a-b949-676b4f127d01?testReportRun=3&testReportShard=1&testReportAttempt=1#targets-Ly9wa2cvdXBncmFkZS91cGdyYWRlbWFuYWdlcjp1cGdyYWRlbWFuYWdlcl90ZXN0) on release-26.2.1-rc @ [3dc9fd1adb98d3dc2cda24ecdba25c354c51a5b0](https://github.com/cockroachdb/cockroach/commits/3dc9fd1adb98d3dc2cda24ecdba25c354c51a5b0):

```
=== RUN TestMigrationFailure
test_log_scope.go:172: test logs captured to: outputs.zip/logTestMigrationFailure3748530506
test_log_scope.go:82: use -show-logs to present logs inline
manager_external_test.go:857: test will fail at version: 26.1-upgrading-to-26.2-step-024
test_server_shim.go:638: DRPC is enabled (via testserver factory defaults)
```

Parameters:
- attempt=1
- race=true
- run=3
- shard=1
Help

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

/cc @cockroachdb/release-eng @cockroachdb/release-eng

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*TestMigrationFailure.*&sort=title+created&display=lastcommented+project) | [Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/bazci/githubpost/issues)

Jira issue: CRDB-63908