Performance updates (#9082)

* Avoid creation of curve legend widgets during construction of a multi plot
* Make sure default z-value is correct to avoid expensive Qwt updates
* Avoid duplicate plot updates
* Do not create internal Qwt legend by default
* RFT import: Avoid expensive method throwing exception if no data is found

ApplicationLibCode/ProjectDataModel/Summary/RimEnsembleCurveSetCollection.cpp

@@ -117,7 +117,7 @@ void RimEnsembleCurveSetCollection::detachPlotCurves()
 {
     for ( const auto& curveSet : m_curveSets )
     {
-        curveSet->detachPlotCurves();
+        curveSet->deletePlotCurves();
     }
 }