fix: added a scroll callback which sets prog step back to 0 on resize

[jlongshore]

Carousel element moving to first step on resize in InterstitialScreen - which is expected behavior... but the navigation and the step indicator was out of sync.

Contributes to 4970

What did you change?

• Added a scroll callback which sets prog step back to 0 on resize
• Modified the story to be more clear on what step you are on
• Updated the stylesheet to use carousels scss - to get the base styles.

How did you test and verify your work?

Storybook

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