The Views Tab Bar has had five tabs until now (Normal, Outline, Notes, Slide
Sorter and Master Handout). Before this commit, selecting the Master Handout
tab and then going back to the Normal or Notes tab showed the Slide/Notes
Master instead of the expected behaviour.

This commit removes the Master Handout Tab from the Views Tab Bar, with master
views remaining accessible through the View Menu.

Change-Id: I017af5f29d154386e4f0910151c478956aa0985f
Reviewed-on: https://gerrit.libreoffice.org/51320Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>