Fix crash caused by disabled serialization of ensemble curves

Fix crash caused by disabled copy of ensemble curves

In 7b269c43d4, the serialization of curve objects for ensemble curves was disabled. This caused the copy operation to produce a new ensemble curve set with empty curve vector.

The setSummaryCaseY operation is not required anymore and therefore removed.

ApplicationLibCode/ProjectDataModel/Summary/RimEnsembleCurveSet.cpp

@@ -2307,11 +2307,6 @@ RimEnsembleCurveSet* RimEnsembleCurveSet::clone() const
     auto copy = copyObject<RimEnsembleCurveSet>();
     copy->setSummaryEnsemble( m_yValuesSummaryEnsemble() );
 
-    // Update summary case references
-    for ( size_t i = 0; i < m_curves.size(); i++ )
-    {
-        copy->m_curves[i]->setSummaryCaseY( m_curves[i]->summaryCaseY() );
-    }
     return copy;
 }