[api-minor] Add partial support for the "GoToE" action (issue 8844)

*Please note:* The referenced issue is the only mention that I can find, in either GitHub or Bugzilla, of "GoToE" actions.
Hence why I've purposely settled for a very simple, and partial, "GoToE" implementation to avoid complicating things initially.[1] In particular, this patch only supports "GoToE" actions that references the /EmbeddedFiles-dict in the PDF document.

See https://web.archive.org/web/20220309040754if_/https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#G11.2048909

---
[1] Usually I always prefer having *real-world* test-cases to work with, whenever I'm implementing new features.

web/app.js

@@ -636,6 +636,7 @@ const PDFViewerApplication = {
       container: appConfig.sidebar.outlineView,
       eventBus,
       linkService: pdfLinkService,
+      downloadManager,
     });
 
     this.pdfAttachmentViewer = new PDFAttachmentViewer({