refactor(pagination): minor nitpicks

- check for null ref in usePagination
- restore original IntersectionObserver in test

packages/components/pagination/__tests__/pagination.test.tsx

@@ -81,6 +81,8 @@ describe("Pagination", () => {
   });
 
   it("the pagination cursor should not have data-moving attribute before intersection", () => {
+    const originalIntersectionObserver = window.IntersectionObserver;
+
     // save callback and options to later emulate intersection event
     let intersectCallback: IntersectionObserverCallback | undefined;
     let intersectOptions: IntersectionObserverInit | undefined;
@@ -148,5 +150,7 @@ describe("Pagination", () => {
 
     // on rerender, the cursor should have the data-moving attribute
     expect(cursor).toHaveAttribute("data-moving");
+
+    window.IntersectionObserver = originalIntersectionObserver;
   });
 });

packages/components/pagination/src/use-pagination.ts

@@ -283,7 +283,9 @@ export function usePagination(originalProps: UsePaginationProps) {
   const [setRef, isVisible] = useIntersectionObserver();
 
   useEffect(() => {
-    setRef(domRef.current);
+    if (domRef.current) {
+      setRef(domRef.current);
+    }
   }, [domRef.current]);
 
   const activePageRef = useRef(activePage);