Tracing: Fix runtime QML warnings

"QML Connections: Implicitly defined onFoo properties in Connections are
deprecated. Use this syntax instead: function onFoo(<arguments>)"

Change-Id: Idf65152f5aa1b96a739bd41f87893270b9da8e1b
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/libs/tracing/qml/FlameGraphView.qml

@@ -307,7 +307,7 @@ ScrollView {
 
             Connections {
                 target: root.model
-                onModelReset: {
+                function onModelReset() {
                     tooltip.hoveredNode = null;
                     tooltip.selectedNode = null;
                 }