DEPS: bump across etcd-io/raft#81 and disable conf change validation

[tbg]

We don't want raft to validate conf changes, since that causes issues due to false positives (the check is above raft, but needs to be below raft to always work correctly). We are
taking responsibility for carrying out only valid conf changes, as we always
have.

See also etcd-io/raft#80.

Fixes #105797.
Epic: CRDB-25287
Release note (bug fix): under rare circumstances, a replication change could get
stuck when proposed near lease/leadership changes (and likely under overload),
and the replica circuit breakers could trip. This problem has been addressed.
Note to editors: this time it's really addressed (fingers crossed); a previous
attempt with an identical release note had to be reverted.

[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?

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[cockroach-teamcity]

This change is 

[tbg]

bors r=erikgrinaker
🚀

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)

[blathers-crl]

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

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2. There was a merge conflict.
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error creating merge commit from 404188d to blathers/backport-release-22.2-106515: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

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

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

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[nvanbenschoten]

@tbg @pav-kv now that we are using DisableConfChangeValidation and we ignore the r.pendingConfIndex > r.raftLog.applied condition here, do we still have a guarantee that a raft leader will never propose a configuration change before it has applied the latest configuration change? In other words, does this change break the Apply and Append invariants from etcd-io/etcd#7625 (comment) for split leaseholder/leader states where the leader is behind on log application? Could that lead to split brain scenarios? cc. @sumeerbhola