startup: retry pgerror.Code == RangeUnavailable

[tbg]

Closes #104016.

Epic: None
Release note (bug fix): a bug was fixed due to which nodes could terminate with the following message:
server startup failed: cockroach server exited with error:
‹migration-job-find-already-completed›: key range id:X is unavailable: ‹failed
to send RPC: no replica node information available via gossip for rX›

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

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

[cockroach-teamcity]

This change is 

[aliher1911]

Good that we could easily plug in any error. 😆 😭

[tbg]

TFTR!

bors r=aliher1911

[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 creating merge commit from df97a99 to blathers/backport-release-22.2-104128: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 22.2.x failed. See errors above.

---

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