[Kickoff] Fix breadcrumb navigation

Workaround for ListModel not being able to store QVariant(QModelIndex)
values. Now it's stored in another model property. Makes the breadcrumb
navigation work again.

BUG: 328654

plasma/desktop/applets/kickoff/package/contents/ui/ApplicationsView.qml

@@ -93,6 +93,8 @@ Item {
                 Repeater {
                     model: ListModel {
                         id: crumbModel
+                        // Array of the category indexes
+                        property var indexes: []
                     }
 
                     Breadcrumb {
@@ -162,8 +164,9 @@ Item {
                 model: Kickoff.ApplicationModel {}
             } // VisualDataModel
 
-            function addBreadcrumb(modelIndex, title) {
-                crumbModel.append({"text": title, "modelIndex": modelIndex, "depth": crumbModel.count+1})
+            function addBreadcrumb(categoryIndex, title) {
+                crumbModel.append({"text": title, "depth": crumbModel.count+1})
+                crumbModel.indexes.push(categoryIndex);
             }
 
             PlasmaCore.Svg {

plasma/desktop/applets/kickoff/package/contents/ui/Breadcrumb.qml

@@ -42,15 +42,16 @@ Item {
         enabled: crumbRoot.depth < crumbModel.count
 
         onClicked: {
-            while (crumbModel.count > 0 &&
-                crumbRoot.depth < crumbModel.get(crumbModel.count-1).depth) {
+            // Remove all the breadcrumbs in front of the clicked one
+            while (crumbModel.count > 0 && crumbRoot.depth < crumbModel.get(crumbModel.count-1).depth) {
                 crumbModel.remove(crumbModel.count-1)
-                }
+                crumbModel.indexes.pop()
+            }
 
             if (crumbRoot.root) {
                 applicationsView.newModelIndex = 0;
             } else {
-                applicationsView.newModelIndex = model.modelIndex;
+                applicationsView.newModelIndex = crumbModel.indexes[index];
             }
             appViewScrollArea.state = "OutgoingRight";
         }