sw content controls: enable data binding for date

The document had a 2022 date in document.xml, but had a 2012 date in
data binding. Writer used to show 2022, while Word picks 2012.

Data binding for dates were disabled in commit
de90c192cb8f1f03a4028493d8bfe9a127a76b2a (sw content controls, plain
text: enable DOCX filter with data binding, 2022-09-19), because the
formatting of those date timestamps were missing, so it was better to
just not update them from data binding, temporarily.

Fix the problem by adding a new read-only DateString property on
SwXContentControl, this way the import filter can set not only the
timestamp but the formatted date as well.

This shares the SwContentControl::GetDateString() code with the UI,
which already had the need in the past to turn a timestamp into a
date string, based on a provided language and date format.

(cherry picked from commit 58002ab85d992c7ac44d8bb4d135246b67aa5cc7)

Conflicts:
sw/source/core/unocore/unomap1.cxx

Change-Id: I842a9483a675f895129a9854caec347be6b6b84e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/141867
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>

0 files changed, 0 insertions, 0 deletions