Cascader: fix a bug that makes the browser jitter in zoom mode (#21207)

packages/cascader/src/cascader.vue

@@ -640,7 +640,7 @@ export default {
       }
 
       if (tags) {
-        const { offsetHeight } = tags;
+        const offsetHeight = Math.round(tags.getBoundingClientRect().height);
         const height = Math.max(offsetHeight + 6, inputInitialHeight) + 'px';
         inputInner.style.height = height;
         this.updatePopper();