User icon and logout feature missing when logged in through Feide

## Description

In regular apps, you can log out by clicking on the user icon in the top right corner while in app-view or on the receipt page.

However, when logged in through Feide, this icon is missing
This means that you can't log out through this feature.

## To Reproduce
1. Log into an app that uses Feide as login method
2. Observe that the top right corner is missing the user icon

## Expected behavior

I would expect that the icon is present in the top right corner, like is the case in regular apps.

Start by reproducing the missing top-right user icon in an app using Feide, then trace the logged-in app-view and receipt-page UI paths in this TypeScript React frontend. Done means the user icon appears for Feide sessions and its logout feature works as it does for regular apps.

Written by the indexing model from the issue text.