fdo#75256 Improve Sifr Iconset

Update the lc_inserttable after a suggestion from Jay Philipz

Change-Id: Ib2914a61ee5c48333384e4af71aaa436651cfa99
Reviewed-on: https://gerrit.libreoffice.org/12233
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>