release-23.2: kvserver: fix reproposals test with pipelined writes

[blathers-crl]

Backport 4/4 commits from #113658 on behalf of @pavelkalinnikov.

/cc @cockroachdb/release

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Before this commit, the test was a no-op reporting 0 metrics. This is due to isOurCommand function which assumed that the key increment request is always the first request in BatchRequest. With pipelined writes, this is not true.

A typical request is:

QueryIntent ["00001-testing",/Min), Increment ["00001-testing",/Min)

In this commit, isOutCommand scans the BatchRequest to find the command.

Before:

observed 0 async write restarts, observed 0/0 injected aborts, 0 injected illegal lease applied indexes
commands reproposed (unchanged): 1
commands reproposed (new LAI): 0

After:

observed 69 async write restarts, observed 0/69 injected aborts, 366 injected illegal lease applied indexes
commands reproposed (unchanged): 1
commands reproposed (new LAI): 297

Fixes #106504
Touches #110551
Epic: none
Release note: none

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Release justification: fixed test

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

• Backports should only be created for serious
  issues or test-only changes.
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If your backport adds new functionality, please ensure that the following additional criteria are satisfied:

• There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
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Also, please add a brief release justification to the body of your PR to justify this
backport.

[cockroach-teamcity]

This change is