🌐 Add Korean translation for `docs/ko/docs/advanced/sub-applications.md` (#4543)

🌐 Add Korean translation for `docs/ko/docs/advanced/sub-applications.md` (#4543)

* This PR translates advanced/sub-applications.md in Korean.

    Test complete

    related: #2017

* Update sub-applications.md

* Update sub-applications.md

* Update sub-applications.md

* remove .DS_Store

* 🎨 [pre-commit.ci] Auto format from pre-commit.com hooks

* Update docs/ko/docs/advanced/sub-applications.md

* Update docs/ko/docs/advanced/sub-applications.md

* Update docs/ko/docs/advanced/sub-applications.md

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>
Co-authored-by: Motov Yurii <109919500+YuriiMotov@users.noreply.github.com>