[JS] carousel tests failed on pipeline

The complete list is https://microsoft.visualstudio.com/AdaptiveCards/_build/results?buildId=42641362&view=logs&j=12f1170f-54f2-53f3-20dd-22fc7dff55f9&t=35f53584-79fc-539f-463c-6471d0663a3a

Here is an example of the test failure

FAIL tests/components/carousel.spec.ts (7.099 s)
● carousels › when parsed from a valid object › should have all of its expected properties and child elements

TypeError: Cannot read property 'timer' of undefined

  65 |
  66 |         it("should have all of its expected properties and child elements", () => {
> 67 |             expect(carouselTheObject.timer).toEqual(carouselConfig.minAutoplayDelay);
     |                                      ^
  68 |             expect(carouselTheObject.getItemCount()).toBe(2);
  69 |             for (let i = 0; i < carouselTheObject.getItemCount(); i++) {
  70 |                 const currentPage = carouselTheObject.getItemAt(i) as CarouselPage;

  at Object.<anonymous> (__tests__/components/carousel.spec.ts:67:38)

Start with tests/components/carousel.spec.ts, especially the failure at line 67, and run the carousel tests to reproduce it. Trace why carouselTheObject is undefined when parsing the valid object; done when the expected timer and child-element assertions pass in the pipeline.