Online: send color preview JSON property to online
- Autofilter has submenus like `filter by font color` and `filter by bg color`
- to display it's color preview in online we some data from core to identify that it's a color base dialog
- this patch will help to add color preview of following
Change-Id: I71c4e276f8c6dd35d6d318ce67cedf9c15a91d29
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/165298
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Szymon Kłos <szymon.klos@collabora.com>