Export DragOverlayProps for typing (#699)

Author: JuAn-Kang

.changeset/export-dragoverlayprops-type.md

@@ -0,0 +1,5 @@
+---
+"@dnd-kit/core": patch
+---
+
+Export `DragOverlayProps` for consumers.

packages/core/src/index.ts

@@ -1,6 +1,7 @@
 export {
   DndContext,
   DragOverlay,
+  DragOverlayProps,
   defaultAnnouncements,
   defaultDropAnimation,
 } from './components';