tdf#31231: don't set charts modified state when !IsEnableSetModified

Modified state  of the chart is part of modified state of owner document:
see SfxObjectShell::IsModified.

So when the document is loading, any updates to its charts don't make the
document modified.

Change-Id: Ie7643ff55bd44f1afe3f796f72c2508ea57f65d0
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/99102
Tested-by: Mike Kaganski <mike.kaganski@collabora.com>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
diff --git a/sc/source/core/data/documen5.cxx b/sc/source/core/data/documen5.cxx
index a06505a..631f60c 100644
--- a/sc/source/core/data/documen5.cxx
+++ b/sc/source/core/data/documen5.cxx
@@ -336,7 +336,7 @@ void ScDocument::UpdateChart( const OUString& rChartName )
    if (!mpDrawLayer || bInDtorClear)
        return;
    uno::Reference< chart2::XChartDocument > xChartDoc( GetChartByName( rChartName ) );
    if( xChartDoc.is() )
    if (xChartDoc && (!mpShell || mpShell->IsEnableSetModified()))
    {
        try
        {