fix: allow scrolling in icon story

[montezume]

Summary

Before #186 , we had

import '../materials/internals/reset.mod.css';	
import './main.mod.css';	

This meant that the overflow: auto took precedence over overflow: hidden in reset.mod.css.

By importing reset.mod.css in index.js, this order of precedence changed.

Approach

Remove overflow: hidden in reset.mod.css because this shouldn't be in UI-Kit anyways.

Release notes Consumers which were relying on overflow: hidden on body now need to define this themselves.