message: Workaround for Safari error when creating PdfWorker
diff: import { PdfRenderer } from 'letter-generator';
  +import type { Class } from 'type-fest';
  onmessage = (e) => {
  const pdf_renderer = new PdfRenderer(e.data.pdfdoc);
  @@ -34,8 +35,4 @@ const vfs_fonts = {
  // The Webpack worker-loader plugin will transform this file to have default export that creates the worker but
  // TypeScript doesn't know that, so we introduce this fake export to trick it.
  -export default class PdfWorker extends Worker {
  - constructor() {
  - super('');
  - }
  -}
  +export default undefined as unknown as Class<Worker>;
  