message: fix(masthead): use window-or-global for window event listener
diff: import React, { useEffect, useState, useRef } from 'react';
  import PropTypes from 'prop-types';
  import { settings } from 'carbon-components';
  +import root from 'window-or-global';
  import { User20, UserOnline20 } from '@carbon/icons-react';
  import { IbmLogo } from '../Icon';
  import {
  @@ -95,13 +96,13 @@ const Masthead = ({ navigation, ...mastheadProps }) => {
  * L0 will hide/show only in the top 25% of the viewport.
  *
  */
  - const handleScroll = window.addEventListener('scroll', () => {
  + const handleScroll = root.addEventListener('scroll', () => {
  if (mastheadL1Ref.current != null) {
  - setSticky(window.pageYOffset > window.innerHeight * 0.25);
  + setSticky(root.pageYOffset > root.innerHeight * 0.25);
  }
  });
  return () => {
  - window.removeEventListener('scroll', () => handleScroll);
  + root.removeEventListener('scroll', () => handleScroll);
  };
  }, []);
  