Update CSS in the classic visual editor link popup to remove sizing in pixels that caused significant text overlaps when the base font size is scaled or set to a larger custom value in the browser or operating system.
Props jonny-s, sabernhardt, joedolson.
Fixes#53174.
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git-svn-id: http://core.svn.wordpress.org/trunk@53775 1a063a9b-81f0-0310-95a4-ce76da25c4cd
