Put right icon in image button

Change-Id: Ieed7b3cc0725b5d3341ed390035c55df8a8119e2
Reviewed-on: https://gerrit.libreoffice.org/7218
Reviewed-by: Olivier Hallot <olivier.hallot@edx.srv.br>
Tested-by: Olivier Hallot <olivier.hallot@edx.srv.br>