message: fix(Collapse): wrapperRef may be undefined
diff: @@ -91,7 +91,9 @@ export default defineComponent({
  // use double raf to ensure animation can start
  doubleRaf(() => {
  - wrapperRef.value!.style.height = value ? contentHeight : '0';
  + if (wrapperRef.value) {
  + wrapperRef.value.style.height = value ? contentHeight : '0';
  + }
  });
  } else {
  onTransitionEnd();
  