lib: remove unused css rule from listing.less

Closes cockpit-project#13000

Author: KKoukiou

pkg/lib/listing.less

@@ -222,7 +222,6 @@ tr.listing-ct-item > td {
 
 /* Listing actions can be used directly as a cell */
 tr.listing-ct-item td.listing-ct-actions,
-caption div.listing-ct-actions,
 td.listing-ct-actions {
     padding: @listing-ct-padding / 2 @listing-ct-padding;
     text-align: right;