Resolves fdo#87558: Duplication in Last Used Functions sidebar list

Change-Id: If15199e205671d3e96e5c2b2940c0a6defced0e0
Reviewed-on: https://gerrit.libreoffice.org/13583
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>