Prevent underline hover on cards (#18259)

Prevent a undesired underline effect on hovered cards.

This was regressed by #17898.

web_src/less/_base.less

@@ -248,6 +248,7 @@ a.label,
 .repository-menu a,
 .ui.search .results a,
 .ui .menu a,
+.ui.cards a.card,
 .issue-keyword a {
   text-decoration: none !important;
 }