Update content/ko/docs/contribute/advanced.md to match latest english version

[vbottu]

Description

This PR updates the Korean translation of the advanced contributing guide to match the English version.

Changes

• Added the missing "Offboarding a SIG Co-chair (Emeritus)" section at the end of the document

The Korean translation was previously missing this final section. I've now added it with the appropriate Korean translation to keep it in sync with the English documentation.

Checklist

• Verified the translation matches the English structure
• Followed Korean localization guidelines
• All sections are now complete and up-to-date

Closes: #53264

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[Eundms]

/assign