menu bar behavior consistency: remove checkbox from disabled menu item

If menu item which can have checkbox is disabled, checkbox is not drawn
near it. After matching to enabled criteria this checkbox can appear and
after disabling menu item again it still remain, so initial and final
state of menu are different.

Change-Id: I31be02da892212e12276aa56bae15e6fa453a5bf
Reviewed-on: https://gerrit.libreoffice.org/50506
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Katarina Behrens <Katarina.Behrens@cib.de>

path: root/icon-themes/elementary_svg/cmd/sc_alignblock.svg

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