web: prevent layout flash for logged-in user

Created by: valerybugakov

Context

Layout flashes on page load from non-logged-in variant to logged-in variant.

https://user-images.githubusercontent.com/3846380/134764071-ce9498b4-c93b-4bf4-85c9-f80f8fee6493.mov

The root cause of the issue

After enabling persistent cache for the viewerSettings query, it's loaded faster than the CurrentAuthState query. This causes the update of the authenticatedUser state to null which enables content rendering despite the fact that the CurrentAuthState request is not completed. The correct value for authenticatedUser is undefined till the CurrentAuthState query completion. It prevents the render function from going past the condition:

if (authenticatedUser === undefined || graphqlClient === undefined) {
      return null
}