fdo#79676: Initialize with a default chart only from the UI.

When creating an embedded chart object during import, we don't want to
create a default chart which would only mess up the chart data.

With this change, ChartModel::initNew() is a no-op.

(cherry picked from commit c5539bb585370f095cb6c09e38a7dd005d237295)

Conflicts:
	chart2/source/model/main/ChartModel_Persistence.cxx
	sc/source/ui/drawfunc/fuins2.cxx
	sw/source/uibase/table/tablemgr.cxx

Change-Id: Id29659c3885ec1e06bed26d2c851123fb63072cc
fdo#79676: Fix the Java UNO API test with regard to chart tests.

The Java tests rely on the "undocumented" behavior that, when loading an empty
chart document, the chart automaticallly created a "default chart" which is a
column chart with many of its properties filled.  Unfortunately this behavior
caused ugly side effects when loading documents with charts via flat ODF
filter.

I believe fixing the test this way is the right fix.

Change-Id: If3e6c8979da9d0731346ebeedc23c0d3363e83fd
(cherry picked from commit d44b58beed743871df03909e7d9545e488f3d7c8)