CNDB-14893: remove unused imports

[driftx]

What is the issue

There are unused imports failing checkstyle

What does this PR fix and why was it fixed

Remove unused imports

[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

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud

[cassci-bot]

❌ Build ds-cassandra-pr-gate/PR-1886 rejected by Butler

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

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Found 36 new test failures

Showing only first 15 new test failures

Test	Explanation	Branch history	Upstream history
...lidation.operations.AlterTest-compression_jdk11	regression	🔴
...nQueryShouldNotTimeoutWhenItExceedesReadTimeout	regression	🔴
...nglePageReadIsFastButAggregationExceedesTimeout	regression	🔴
...adCommitLogAndSSTablesWithDroppedColumnTestCC40	regression	🔴
...adCommitLogAndSSTablesWithDroppedColumnTestCC50	regression	🔴
...oadCommitLogAndSSTablesWithDroppedColumnTestDSE	regression	🔴
...thRestartTest.testReadingValuesOfDroppedColumns	regression	🔴
o.a.c.d.t.s.f.FeaturesVersionSupportDBTest.testANN	regression	🔴
o.a.c.d.t.s.f.FeaturesVersionSupportDCTest.testANN	regression	🔴
o.a.c.d.t.s.f.FeaturesVersionSupportEBTest.testANN	regression	🔴
...c.FeaturesVersionSupportTest.testANNSupport[eb]	regression	🔴
....FeaturesVersionSupportTest.testGeoDistance[aa]	regression	🔴
....FeaturesVersionSupportTest.testGeoDistance[ba]	regression	🔴
....s.f.SnapshotTest.shouldTakeAndRestoreSnapshots	regression	🔴
...cySSTableTest.testVerifyOldDroppedTupleSSTables	regression	🔴

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No known test failures found