docs: remove unnecessary code (#25738)

Co-authored-by: zhanghaoqiang <zhanghaoqiang@focusmedia.cn>

components/table/demo/virtual-list.md

@@ -74,7 +74,7 @@ function VirtualTable(props) {
         }}
         height={scroll.y}
         rowCount={rawData.length}
-        rowHeight={() => 54}
+        rowHeight={54}
         width={tableWidth}
         onScroll={({ scrollLeft }) => {
           onScroll({ scrollLeft });