Fix disabled Dropdown Items not showing Popup component

For the `src/components/CollectionDetailPage/CollectionContextMenu/CollectionContextMenu.tsx` component, the `Popup` are not being displayed when the `Dropdown.item` is disabled. There is a similar use case and a fix was introduced [here](https://github.com/decentraland/builder/pull/1800/files#r809825102). We need to move that same workaround to a `/src/themes/components/Dropdown.cs` so we fix it everywhere.