roachtest: pin liveness lease to live node in lease prefs test

[kvoli]

The lease preferences roachtest could occasionally fail, if the liveness leaseholder were on a stopped node. We should address this issue, for now, pin the liveness lease to a live node to prevent flakes.

Informs: #108512
Resolves: #108425
Release note: None

[cockroach-teamcity]

This change is 

[kvoli]

Tyftr!

Bors r=erikgrinaker

[kvoli]

bors r-

[kvoli]

bors r=erikgrinaker

[craig]

Canceled.

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error setting reviewers, but backport branch blathers/backport-release-23.1-108517 is ready: POST https://api.github.com/repos/cockroachdb/cockroach/pulls/108544/requested_reviewers: 422 Reviews may only be requested from collaborators. One or more of the teams you specified is not a collaborator of the cockroachdb/cockroach repository. []

Backport to branch 23.1.x failed. See errors above.

---

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[kvoli]

blathers backport release-23.1.9-rc

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

---

error setting reviewers, but backport branch blathers/backport-release-23.1.9-rc-108517 is ready: POST https://api.github.com/repos/cockroachdb/cockroach/pulls/109129/requested_reviewers: 422 Reviews may only be requested from collaborators. One or more of the teams you specified is not a collaborator of the cockroachdb/cockroach repository. []

Backport to branch release-23.1.9-rc failed. See errors above.

---

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}