fix(Tree): beforeRightClick type (#2968)

src/components/Tree/src/types/tree.ts

@@ -105,7 +105,7 @@ export const treeProps = buildProps({
   },
 
   beforeRightClick: {
-    type: Function as PropType<(...arg: any) => ContextMenuItem[] | ContextMenuOptions>,
+    type: Function as PropType<(...arg: any) => Promise<ContextMenuItem[] | ContextMenuOptions>>,
     default: undefined,
   },