release-23.1: sql: fix TestCaptureIndexUsageStats

[blathers-crl]

Backport 1/1 commits from #110639 on behalf of @maryliag.

/cc @cockroachdb/release

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Tests can take longer to be completed, so a bigger time buffer
would be required to accomodate for the non-determinism in
the logging timings. This time buffer has been increasing every
couple of months and it would have to change to 5s now, which is
a big buffer compared to the actual value of 1s. The time it takes
is not really relevant for this test, as long as the schedules
are happening one after the other.
So instead of increasing the time buffer even more, this commit
removes those checks. This way the test is no longer flaky or would need
to be adjusted every few months, and we keep all the actual checks
important for the test.

Fixes #110617

Release note: None

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Release justification: test-only fix

[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 

[THardy98]

LGTM