Break import cycles, in the viewer, for PDFViewerApplication

Currently the `web/app.js` file pulls in various build-specific dependencies, via the use of import maps, and those files in turn import from `web/app.js` thus creating undesirable import cycles.
To avoid this we instead pass in a `PDFViewerApplication`-reference, immediately after it's been created, to the relevant code.

Note that we use an ESLint plugin rule, see `import/no-cycle`, that is normally able to catch import cycles. However, in this case import maps are involved which is why this wasn't caught.

web/interfaces.js

@@ -221,6 +221,8 @@ class IL10n {
  * @interface
  */
 class IPDFPrintServiceFactory {
+  static initGlobals() {}
+
   static get supportsPrinting() {
     return false;
   }