Also assign space when adjusting to item size hints

We release space but never assign new space for the item so we end up thinking
the space that the item ends up occupying is free.

components/containmentlayoutmanager/gridlayoutmanager.cpp

@@ -321,6 +321,7 @@ void GridLayoutManager::adjustToItemSizeHints(ItemContainer *item)
     if (changed && itemIsManaged(item)) {
         releaseSpace(item);
         positionItem(item);
+        assignSpace(item);
     }
 }