release-24.3.1-rc: security: bugfix, ensure cert expiry metrics reflect reloaded certs

[angles-n-daemons]

Backport 1/1 commits from #135596.

/cc @cockroachdb/release

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security: bugfix, ensure cert expiry metrics reflect reloaded certs

The PR #130110 added certificate TTL metrics alongside our existing expiration metrics. Prior to that change, the certificate metrics values were updated on each metrics load. Afterwards, new metrics objects were created for each load of certificates.

This created a bug in that the new expiration values would not be found in any of the system exhaust (metrics scrape or tsdb) because the registered metrics objects were the ones created on startup.

This new change instead allows the metrics to close the whole CertificateManager object, so that they only need to be created once, and therefore the initial registration of metrics reflects persistently valid values.

Release note (bug fix): security.certificate.* metrics will now be updated if a node loads new certificates while running.

Epic: none
Fixes: #135093

Release justification: Fixes a bug in the certificate metrics.

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

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  issues or test-only changes.
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[cockroach-teamcity]

This change is