release-22.1: kvserver: ignore leaseholder replica type in DistSender

[erikgrinaker]

Backport 1/1 commits from #85140.

/cc @cockroachdb/release

Release justification: fixes a latency regression in 22.1.

---

The DistSender could fail to prioritize a newly discovered leaseholder
from a NotLeaseHolderError if the leaseholder had a non-VOTER
replica type. Instead, it would continue to try replicas in order until
possibly exhausting the transport and backing off, leading to increased
tail latencies. This applies in particular to 22.1, where we allowed
VOTER_INCOMING replicas to acquire the lease (see 22b4fb5).

The primary reason is that grpcTransport.MoveToFront() would fail to
compare the new leaseholder replica descriptor with the one in its range
descriptor. There are two reasons why this can happen:

1. ReplicaDescriptor.ReplicaType is a pointer, where the zero-value
   nil is equivalent to VOTER. The equality comparison used in
   MoveToFront() is ==, but pointer equality compares the memory
   address rather than the value.

2. The transport will keep using the initial range descriptor when it
   was created, and not updating it as we receive updated range
   descriptors. This means that the transport may e.g. have a nil
   replica type while the leaseholder has an VOTER_INCOMING replica
   type.

This patch fixes both issues by adding ReplicaDescriptor.IsSame()
which compares replica identities while ignoring the type.

Resolves #85060.
Touches #74546.

Release note (bug fix): Fixed a bug where new leaseholders (with a
VOTER_INCOMING type) would not always be detected properly during
query execution, leading to occasional increased tail latencies due
to unnecessary internal retries.

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

• Patches should only be created for serious issues or test-only changes.
• Patches should not break backwards-compatibility.
• Patches should change as little code as possible.
• Patches should not change on-disk formats or node communication protocols.
• Patches should not add new functionality.
• Patches must not add, edit, or otherwise modify cluster versions; or add version gates.

If some of the basic criteria cannot be satisfied, ensure that the exceptional criteria are satisfied within.

• There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
• The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
• New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters.
• The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.

Add a brief release justification to the body of your PR to justify this backport.

Some other things to consider:

• What did we do to ensure that a user that doesn’t know & care about this backport, has no idea that it happened?
• Will this work in a cluster of mixed patch versions? Did we test that?
• If a user upgrades a patch version, uses this feature, and then downgrades, what happens?

[cockroach-teamcity]

This change is