release-26.1: kvserver: stop wrapping AbortSpan errors as ReplicaCorruptionError

[tbg]

Backport 1/2 commits from #167295.

/cc @cockroachdb/release

---

AbortSpan read errors were wrapped as ReplicaCorruptionError, causing the
node to fatal via setCorruptRaftMuLocked. This was overly aggressive: a
failure to read from the AbortSpan is not indicative of replica corruption.
Transient I/O errors would crash the node instead of being returned to the
caller.

This is the last remaining production call site that produces
ReplicaCorruptionError (the split/merge trigger wrapping was removed in
#167289).

Informs: #165558
Epic: none

Release justification: Low-risk bug fix. One-line change that stops wrapping
a non-corruption error as ReplicaCorruptionError, preventing unnecessary
node crashes on transient I/O errors during AbortSpan reads.

[trunk-io]

😎 Merged successfully - details.

[blathers-crl]

Thanks for opening a backport.

Before merging, please confirm that the change does not break backwards compatibility and otherwise complies with the backport policy. Include a brief release justification in the PR description explaining why the backport is appropriate. All backports must be reviewed by the TL for the owning area. While the stricter LTS policy does not yet apply, please exercise judgment and consider gating non-critical changes behind a disabled-by-default feature flag when appropriate.

[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 

[blathers-crl]

Detected infrastructure failure (matched: self-hosted runner lost communication with the server). Automatically rerunning failed jobs. (run link)