Improve sub-widget hover highlighting in ListItem2

[abey79]

Currently, the hover highlight of the list item is dimmed when sub-widget (e.g. action button, etc.) is highlighted. This is not ideal because it draws the attention to the background instead of the sub-widget. Instead, the sub-widget should have brighter highlight colours, such that the list item's hover highlight can remain the same and the sub-widget's highlight still be visible.