chore: upgrade prettier to 3.9.6 - #41807

No issues found. Spectre coverage incomplete: selected 14, scanned 14, skipped 0, oversized 1, capped 76, truncated 0, failed 0, invalid 0, rejected 0, repairs 0, repaired responses 0, repaired findings 0, cancelled 0, rate-limited 0, concurrency-limited 0, circuit-open 0. Reason: file-cap-exceeded. Adapter coverage incomplete: semgrep (scanner-errors-reported).