message: Set the initial Storybook theme to light
  This fixes the inconsistency if user's OS/Browser theme is set to Dark mode.
diff: import React from 'react';
  -import { addDecorator } from '@storybook/react';
  +import { addDecorator, addParameters } from '@storybook/react';
  import { lightTheme, darkTheme } from '@backstage/theme';
  import { CssBaseline, ThemeProvider } from '@material-ui/core';
  import { useDarkMode } from 'storybook-dark-mode';
  import { Content } from '@backstage/core';
  -addDecorator(story => (
  +addDecorator((story) => (
  <ThemeProvider theme={useDarkMode() ? darkTheme : lightTheme}>
  <CssBaseline>
  <Content>{story()}</Content>
  </CssBaseline>
  </ThemeProvider>
  ));
  +
  +addParameters({
  + darkMode: {
  + // Set the initial theme
  + current: 'light',
  + },
  +});
  