fix ui package and storybook

As I mentioned in the #dev-team, the ui package needs a css here so that storybook will be able to distinguish between css from two ui libraries (ui/ui-v2) instead of using one globally. The original stuff here were just removed by merger.

If we don't make changes here, the result will be that the ui-related components in storybook will not be able to call the custom class names in packages/ui/src/styles/tailwind.css.