So the implementation is somewhat dirty.
The ideas was nice - add lostFocusHandler
However it broke few things:
* In the TabSwitcher the ListItem must be focusable since otherwise
the SingleSelectionMode behavior breaks.
To address this I had to put the lostFocusHandler on the items as well
* When you click the flyout, the palette loses focus,
which makes the terminal page to set the focus on the tab, closing the flyout.
To address this I had to ensure the tab won't get focused once the flyout is open.
In addition, flyout should fix the focus before opening,
otherwise alt+tab will put a focus on a tab row rather than on tab
* I also had to close the palette if the tab order changes.
To prevent inconsistencies.
Closes#8355
e1a8657370