QmlDesigner: Fix crashes in connection view

- Fix for connections order in view
 - Fix for binding and connection editor init crash

Change-Id: If0faf401b8e89a5548c65f07284138e869612c95
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/components/connectioneditor/connectionmodel.cpp

@@ -219,9 +219,6 @@ void ConnectionModel::updateTargetNode(int rowNumber)
             connectionNode.bindingProperty("target").setExpression(newTarget);
         });
 
-        QStandardItem* idItem = item(rowNumber, 0);
-        updateCustomData(idItem, signalHandlerProperty);
-
     } else {
         qWarning() << "BindingModel::updatePropertyName invalid target id";
     }