Tweak 2 dialogs for Calc Data Statistics, seeking consistency and using HIG guidelines

Change-Id: Ie87413dd820315eaf68eafdbd7381ec1f3744b4d
Reviewed-on: https://gerrit.libreoffice.org/10673Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
Tested-by: Tomaž Vajngerl <quikee@gmail.com>