With nested blocks the inner block was still logged in when the test
tried to visit the login page of the secondary node, so the page
failed validation because it was already logged in.

This moves the secondary sessions outside the primary session block
so that the primary session ends and the secondary session can login.

It also logs out after each test so that subsequent tests aren't logged
in. Resetting the browser session (by using a visit block) isn't enough
to log out subsequent sessions