Widgets: Remove unused CSS breaking wp_text_diff layout.

Remove CSS used in version of `wp_text_diff` prior to [50034]. Orphaned CSS breaks default layout of function output, but is overridden in the revisions screen.

Props mt8.biz, hareesh-pillai, mukesh27.
Fixes #54140.
Built from https://develop.svn.wordpress.org/trunk@51972


git-svn-id: http://core.svn.wordpress.org/trunk@51561 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/revisions-rtl.css

@@ -187,10 +187,6 @@ body.folded .revisions .loading-indicator {
 	vertical-align: middle;
 }
 
-table.diff tbody tr td:nth-child(2) {
-	width: 4%;
-}
-
 table.diff {
 	table-layout: fixed;
 	width: 100%;

wp-admin/css/revisions.css

@@ -186,10 +186,6 @@ body.folded .revisions .loading-indicator {
 	vertical-align: middle;
 }
 
-table.diff tbody tr td:nth-child(2) {
-	width: 4%;
-}
-
 table.diff {
 	table-layout: fixed;
 	width: 100%;