Fix race condition in WriteBufferFromS3 with TSA annotations

Why it matters

This fix addresses a race condition in the WriteBufferFromS3 class that could lead to unpredictable behavior or data corruption during concurrent writes to Amazon S3 storage. Adding TSA annotations improves code quality by enabling static analysis tools to verify thread safety, thereby reducing concurrency bugs.

How to use it

Users benefit from this fix automatically when they upgrade to the new ClickHouse version containing the patch. No additional configuration or usage changes are required as this is an internal stability improvement.