release-23.1: server: allow users with VIEWACTIVITY to get console settings

[maryliag]

Backport 1/1 commits from #108486.

/cc @cockroachdb/release

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Previously, only users with ADMIN, VIEWCLUSTERSETTING or MODIFYCLUSTERSETTING could get the settings on the _admin/v1/settings. This API was used by the Console and then a few places retrieved that information.
Users without those permissions would not be able to see the values and some functionalities where not working as expected, for example timezone was showing as UTC even when the cluster setting ui.display_timezone was set to other value.

This commits modifies that endpoint (and that endpoint only) to return just the cluster settings that are not sensitive and that are required by the console to have all functionalities working.

The list of cluster settings:
"cross_cluster_replication.enabled",
"keyvisualizer.enabled",
"keyvisualizer.sample_interval",
"sql.index_recommendation.drop_unused_duration",
"sql.insights.anomaly_detection.latency_threshold", "sql.insights.high_retry_count.threshold",
"sql.insights.latency_threshold",
"sql.stats.automatic_collection.enabled",
"timeseries.storage.resolution_10s.ttl",
"timeseries.storage.resolution_30m.ttl",
"ui.display_timezone",
"version"

Part Of #108373
Fixes #108117

Release note (bug fix): Users with VIEWACTIVITY can now view correct values for timezone.

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Release justification: Bug 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?

[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 

[abarganier]

LGTM from an obs-infra perspective, but will leave the final approval to cluster-obs

Reviewable status: complete! 0 of 0 LGTMs obtained

[gtr]

Reviewed 2 of 3 files at r1, 1 of 1 files at r2, all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @maryliag)