Can I disable this in components.xml?
I don't believe so.
You can control conversation propagation in several ways, for example, in pages.xml. As you noted, Seam always creates a conversation, but you don't necessarily have to propagate that conversation unless that is what you want to do, in which case it becomes a
long runningconversation. Perhaps you can find a solution in chapter 7 of the Seam reference manual.