fdo#71595 use F9 for recalculation of RAND function

Ctrl+Shift+F9 recalculates all formulas which is not necessary

Change-Id: Id87738fbed8d0079b2ece2dbb779fa134d34ac89
Reviewed-on: https://gerrit.libreoffice.org/6703
Tested-by: Thorsten Behrens <thb@documentfoundation.org>
Reviewed-by: Thorsten Behrens <thb@documentfoundation.org>