message: refactor: Prefer canUseDOM over typeof window
diff: +import { canUseDOM } from '@vkontakte/vkjs';
  +
  // eslint-disable-next-line no-restricted-globals
  -export const isTesting = Boolean(typeof window !== 'undefined' && (window as any).__isVkuiTesting);
  +export const isTesting = Boolean(canUseDOM && (window as any).__isVkuiTesting);
  