fix(dashboard): clear "1 item selected" when a double-click opens a file

Opening a file by double-click deselects its row, but the footer kept
saying "1 item selected" with nothing selected.

src/gui/src/UI/Dashboard/TabFiles.js

@@ -3234,6 +3234,7 @@ const TabFiles = {
                 open_item({ item: el_item });
             }
             el_item.classList.remove('selected');
+            _this.updateFooterStats();
         };
 
         // --------------------------------------------------------