[User guide] Add animation on complete to UserGuideStep

### Description

We would like to trigger the animation now managed by the isCompleted prop in the standard UserGiode step as it is the last step of the HomeTour. 

### Design

https://design.livechat.com/?path=/story/components-userguide--user-guide-bubble-step-example-with-animation&globals=backgrounds.grid:!false;theme:light