Keyboard navigation for AccountBar is wrong

[erikjv]

When using the narrator, and using the keyboard to navigate: when pressing "space" to switch from e.g. settings to an account, the narrator will only say "space", and not say that an account pane is now active.

Same for VoiceOver.

[erikjv]

Selection should work different: when the tab "focus" is changed, the new tab should be foregrounded immediately

[TheOneRing]

The current bar is a mix of a tab and button bar, the current behavior is suboptimal, but any solution would require a conceptual redesign of the bar.