Fix mis-alignment of the "Login again" button

[Nicklas Nordborg]

When a user that has been automatically logged out returns to BASE, a "Not logged in" message is displayed. Everything works as expected but one annoying thing is that the "Login again" button is not centered.

The reason for this is that the same page is also used in pop-up windows but then also has a "Close" button. In this case, the two buttons are centered. In a regular (not popup) window, the "Close" button is hidden which causes the "Login again" button to be mis-aligned.

[Nicklas Nordborg]

In 7795:

Fixes #2204: Fix mis-alignment of the "Login again" button

This dialog now uses 2 different groups of buttons. One group with "Close" and "Login again" and one group with only a "Login again" button. Only one of the groups is displayed for a given page so the buttons should always be center-aligned now.