DesignTokens: Update bindings on property value change

Fixes: QDS-15125
Change-Id: I2492951f7b184b05e65374062219087040fb9bf3
Reviewed-by: Henning Gründl <henning.gruendl@qt.io>

src/plugins/qmldesigner/components/designsystemview/collectionmodel.cpp

@@ -253,6 +253,7 @@ bool CollectionModel::setData(const QModelIndex &index, const QVariant &value, i
             updateCache();
 
             emit dataChanged(index, index);
+            updateBoundValues();
             result = true;
         }
     }