No, you can't, and this is a security feature.

Teams usually have different teammates that have access to the documents shared in the team. If you move a document from one team it would be shared between the members in the new team, even if you haven't uploaded the document yourself. Since Konfident has a very simple drag-and-drop interface it would be too easy to move a document to another team by mistake. 

If you need to share the document with another team you must first download it, and then upload it again to the other team, minimising the risk of making a simple mistake.