There were two issues:
- we did not find VDom roots inside shadow DOM
- we incorrectly relied on DOM's `contain` method to determine if
VDom's rendered node belongs to requested scope.
Fixes#10123
This patch adds support for the `vue` selector engine that allows
selecting DOM elements based on the component name.
> **NOTE**: `vue` engine supports Vue2 and Vue2.
References #7189
