[Bug Report] ElScrollbar throws TypeError: Cannot read property '__resizeListeners__' of undefined

### Element UI version
2.13.2

### OS/Browsers version
macOS 10.15.6 / Chrome 85.0.4183.83

### Vue version
2.6.12

### Reproduction Link
https://codepen.io/codeapi/pen/qBZxadX

### Steps to reproduce
1. Create `el-dialog` and add `destroy-on-close`
2. In dialog add `el-tooltip` and put `el-select` inside
3. Open dialog
4. Close dialog -> error occurs

### What is Expected?
No error

### What is actually happening?
```
TypeError: Cannot read property '__resizeListeners__' of undefined
at Ye (index.js:1)
at VueComponent.mounted (index.js:1)
at invokeWithErrorHandling (vue.js:1863)
at callHook (vue.js:4220)
at Object.insert (vue.js:3146)
at invokeInsertHook (vue.js:6341)
at VueComponent.patch [as __patch__] (vue.js:6558)
at VueComponent.Vue._update (vue.js:3949)
at VueComponent.updateComponent (vue.js:4067)
at Watcher.get (vue.js:4478)
```

-----
```
[Vue warn]: Error in mounted hook: "TypeError: Cannot read property '$el' of undefined"

found in

---> at packages/select/src/select-dropdown.vue
at packages/select/src/select.vue

at packages/dialog/src/component.vue

```