Support ability to return compact JSON format when calling SerializeAsJsonAsync

Is your feature request related to a problem? Please describe.
I would like to obtain a compact json format when calling OpenApiSerializableExtensions.SerializeAsJsonAsync

Describe the solution you'd like
That could be done by adding an optional OpenApiJsonWriterSettings parameter to the SerializeAsJsonAsync method (with Terse = true if compact format needed)

Describe alternatives you've considered
Currently i can parse and re-serialize json to obtain a minified format but it would be better to just be able to have the right format immediately.

Additional context
I'm able to propose a pull request if needed.

OpenApiSerializableExtensions.SerializeAsJsonAsync から始めて、現在 JSON writer の設定がどのように処理されているかを確認してください。Issue で説明されているオプションの OpenApiJsonWriterSettings のサポートを追加し、Terse がコンパクトな JSON を生成することを検証して、利用可能であれば既存のシリアル化テストを実行してください。