CNDB-15537: GuardrailsConfig validates

[driftx]

What is the issue

GuardrailsOptions never calls validate() on the configuration so exceptions aren't thrown, which breaks the GuardrailsConfigUpdaterTest

What does this PR fix and why was it fixed

Calls validate(), fixes #15537

[github-actions]

Checklist before you submit for review

• This PR adheres to the Definition of Done
• Make sure there is a PR in the CNDB project updating the Converged Cassandra version
• Use NoSpamLogger for log lines that may appear frequently in the logs
• Verify test results on Butler
• Test coverage for new/modified code is > 80%
• Proper code formatting
• Proper title for each commit staring with the project-issue number, like CNDB-1234
• Each commit has a meaningful description
• Each commit is not very long and contains related changes
• Renames, moves and reformatting are in distinct commits
• All new files should contain the DataStax copyright header instead of the Apache License one

[cassci-bot]

❌ Build ds-cassandra-pr-gate/PR-2032 rejected by Butler

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1 regressions found
See build details here

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Found 1 new test failures

Test	Explanation	Runs	Upstream
o.a.c.index.sai.cql.datamodels.QueryWriteLifecycleWithCompositePartitionKeyTest.terminated successfully ()	<span title="The test is NOT RUN on upstream but has a SINGLE FAILURE on feature:
• Feature branch: a SINGLE FAILURE in 1 builds (1 to 1)
• Upstream branch: MISSING in the last run in 9 builds (147 to 156)">NEW	🔴	0 / 9

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Found 5 known test failures

[djatnieks]

I think the real root problem here is that when I originally worked on guardrails in CC and CNDB I didn't have a validate method at all in CC - this was recently corrected - and then on the CNDB side in GuardrailsConfigUpdaterTest I left out the call to validate in GuardrailsConfigUpdater.updateField (since it didn't exist).

So, I think we should fix CNDB GuardrailsConfigUpdater.updateField to now call validate, e.g.

        try
        {
            // Validate the new guardrail config
            new GuardrailsOptions(config).validate();
        }

I had a comment saying "validate" but the code didn't call it like the CNDB main branch code does (since it didn't exist yet in CC 5.0).

[driftx]

That makes sense, closing this in favor of doing that.