Fix the toolbar text if the interface were RTL.
Remove duplicate code from PresenterToolBar.cxx

Change-Id: Icd6f71ce2daa896494c8efe76779d49e16c547bf
Reviewed-on: https://gerrit.libreoffice.org/1474Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>