[JDBC-V2] fix(StatementImpl/PreparedStatementImpl): prevent duplicate data insertion by clearing batch after execution for issue-2548

[potoo0]

Summary

• Override clearBatch for PreparedStatementImpl
• Clears the internal batch state immediately after executeBatch() to prevent parameter leakage and enable safe statement reuse.

Closes #2548

Checklist

Delete items not relevant to your PR:

• Closes [jdbc-v2] Critical: executeBatch reuse causes duplicate data insertion after 0.8.6 #2548
• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG
• For significant changes, documentation in https://github.com/ClickHouse/clickhouse-docs was updated with further explanations or tutorials

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[chernser]

@potoo0 please sign CLA

[chernser]

This change requires tests. I see only example code change (what is should not be).

Thanks!

[potoo0]

This change requires tests. I see only example code change (what is should not be).

@chernser
Thanks for the review! I've added the tests for this change.