fix(@react-aria/overlays): prevent exception on Cypress

Cypress screenshot command triggers a scroll event where the event target is window, not a DOM element.

closes #2340

packages/@react-aria/overlays/src/useCloseOnScroll.ts

@@ -36,8 +36,8 @@ export function useCloseOnScroll(opts: CloseOnScrollOptions) {
 
     let onScroll = (e: MouseEvent) => {
       // Ignore if scrolling an scrollable region outside the trigger's tree.
-      let target = e.target as HTMLElement;
-      if (!triggerRef.current || !target.contains(triggerRef.current)) {
+      let target = e.target;
+      if (!triggerRef.current || !(target instanceof  HTMLElement) || !target.contains(triggerRef.current)) {
         return;
       }