The width of an tab item is now reduced and is increased by the
icon width when the protected icon needs to be drawn (so on
demand).

Change-Id: Ib4a4742b28ebab21d33e9408e3c416b1f28c6ac2
Reviewed-on: https://gerrit.libreoffice.org/73208
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>