Bug 1865238 - Use One UI Sans KR VF for Korean sans-serif font on Android r=jfkthame

Per /etc/fonts.xml, there are now only two `<family lang="ko">` nodes there:

* OneUISansKRVF series
* SECCJK series (but no KR postfix anymore?)

This patch uses One UI Sans KR VF as the replacement as this is newer and is a variable font (tested with https://codepen.io/SaschaNaz/pen/ExrdYXJ)

Differential Revision: https://phabricator.services.mozilla.com/D195078