CNDB-17161-main: Added method to wait index builds at CFS initialization and fix SSTableContextManager#sstableDescriptors cache on SAI initialization

[jasonstack]

What is the issue

CNDB-17161

What does this PR fix and why was it fixed

Added method to wait index builds at CFS initialization and fix SSTableContextManager#sstableDescriptors cache on SAI initialization

[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

[jasonstack]

Not sure why sonarqubecloud doesn't find the test coverage.. @pkolaczk is there a walkaround?

[pkolaczk]

@jasonstack Yesterday I had the same issue with another PR. I don't know a workaround other than:
checking coverage manually (in IDE) and then bypassing the merge rules.

[jasonstack]

@pkolaczk the release PR has 100% coverage in #2292 (comment). Do you have permission to bypass the gate?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[cassci-bot]

❌ Build ds-cassandra-pr-gate/PR-2302 rejected by Butler

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5 regressions found
See build details here

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Found 5 new test failures

Test	Explanation	Runs	Upstream
o.a.c.distributed.test.sai.SlowSAIQueryLoggerTest.testSlowSAIQueryLogger	REGRESSION	🔴🔴	2 / 30
o.a.c.index.sai.cql.VectorCompaction100dTest.testZeroOrOneToManyCompaction[version=ec enableNVQ=false]	REGRESSION	🔴⚪	0 / 30
o.a.c.index.sai.cql.VectorSiftSmallTest.testRerankKZeroOrderMatchesFullPrecisionSimilarity[version=fa enableNVQ=false enableFused=false]	REGRESSION	🔴⚪	0 / 30
o.a.c.index.sai.cql.VectorTypeTest.nullVectorTest[version=ca enableNVQ=false enableFused=false]	REGRESSION	🔴⚪	0 / 30
o.a.c.utils.binlog.BinLogTest.testTruncationReleasesLogSpace (compression)	REGRESSION	🔵🔴	0 / 30

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Found 9 known test failures