[Bug Report] “expand-row-keys” does not work when setting table data asynchronously #16449
Description
Element UI version
2.10.1
OS/Browsers version
win7
Vue version
2.6.10
Reproduction Link
https://codepen.io/anon/pen/pXxaMz
Steps to reproduce
设置expandRowKeys，ajax获取数据为表格赋值，expandRowKeys无效
What is Expected?
expand-row-keys设置的行应该正常展开
What is actually happening?
行没有展开