CNDB-14614-re-merge: abort compaction task or index build if index is unloaded after tenant unassignment (#1766)

[driftx]

When schema is unloaded after tenant unassignment, compaction task might finishes without corresponding index files, making index non-queryable.

Replace isValid with isDropped and isUnloaded. If index is dropped, compaction task or index build can proceed without the index, same behavior as before. If index is unloaded, compaction task or index build will be aborted to avoid completing without index files.

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#1754 was reverted because CNDB PR compiled failed with wrong hash. Re-merge it again.

[github-actions]

Checklist before you submit for review

• 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

[driftx]

nowInSec from int to long

[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-1828 rejected by Butler

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12 new test failure(s) in 1 builds
See build details here

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Found 12 new test failures

Test	Explanation	Branch history	Upstream history
....r.PendingAntiCompactionTest.testRetriesTimeout	regression	🔴
...adCommitLogAndSSTablesWithDroppedColumnTestCC40	regression	🔴
...adCommitLogAndSSTablesWithDroppedColumnTestCC50	regression	🔴
...oadCommitLogAndSSTablesWithDroppedColumnTestDSE	regression	🔴
...thRestartTest.testReadingValuesOfDroppedColumns	regression	🔴
o.a.c.d.t.r.ForceRepairTest.forceWithDifference	regression	🔴
...estIndexRebuildWhenAddingSStableViaRemoteReload	regression	🔴
...cySSTableTest.testVerifyOldDroppedTupleSSTables	regression	🔴
...m.TrieMemtableMetricsTest.testContentionMetrics	regression	🔴
o.a.c.n.NodesPersistenceTest.testUpdateTokens	regression	🔴
o.a.c.t.SSTablePartitionsTest.testDirectory	regression	🔴
o.a.c.u.b.BinLogTest.testTruncationReleasesLogS...	regression	🔴

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No known test failures found