... otherwise Excel would reset data formatting e.g. from currency
to plain numbers upon refresh.

Excel relies on per-field format setting in pivot tables, while Calc
takes fields formatting from source.

Change-Id: Ia8cdf3f8fcd23720e3daaf989152c170057b339c
Reviewed-on: https://gerrit.libreoffice.org/70860Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Tested-by: Mike Kaganski <mike.kaganski@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/70919