Fetch user's external accounts via user and not site
Created by: artemruts
Description
Fixes #18269 (closed)
Previously errors where thrown when non-admin users tried to access their external accounts through the site
GraphQL node, that's not ok. Only admins can access site
- that's why we saw errors.
Now users will use correct user
node instead.
Tests
With both admin and non-admin users and with non-admin users trying to access other user's external accounts.