DomHelperOverrideGetCommonAncestor

In some cases root LWC element might report that it doesn't contain own children:

to.parentElement....parentElement === from // true
from.contains(to) // false

At the same time shadow root reports it correctly:

from.parentElement.contains(to) // true

It means that method goes one level too high and we need to take first child of the shadow root.