ICONS: Add duplicate reference for flip commands in impress/draw

Change-Id: Id729fd5e8475e48a20645d58f458d5898c9a255a
Reviewed-on: https://gerrit.libreoffice.org/13637
Reviewed-by: Yousuf Philips <philipz85@hotmail.com>
Tested-by: Yousuf Philips <philipz85@hotmail.com>