Usability improvement for direct asset upload. Make the upload action available even when an existing asset is selected. It doesn't make sense to users why they can't upload an asset. The default assumption shouldn't be that the user is trying to replace the existing asset or build a hierarchy. They just want to upload the asset quickly.

This is a common use case when overwriting teaser assets. The Assets chooser dialog won't allow direct upload when the prior asset is selected, which it is by default.

Comparable example: In Google Drive, you can have an existing document selected but you can still upload a new one. The new doc won't replace the selected one or go under it. It will become a sibling.