Make sure the scripting manager is correctly reset when setting a null document

It should fix the error:
```
JavaScript warning: http://127.0.0.1:35021/build/generic/build/pdf.sandbox.mjs, line 192: Script terminated by timeout at:
dispatchEvent@http://127.0.0.1:35021/build/generic/build/pdf.sandbox.mjs:192:3
dispatchEventInSandbox/<@http://127.0.0.1:35021/build/generic/web/viewer.mjs:3177:30
setTimeout handler*dispatchEventInSandbox@http://127.0.0.1:35021/build/generic/web/viewer.mjs:3177:15
async*#dispatchPageClose@http://127.0.0.1:35021/build/generic/web/viewer.mjs:8409:50
async*setDocument/<@http://127.0.0.1:35021/build/generic/web/viewer.mjs:8172:36
dispatch@http://127.0.0.1:35021/build/generic/web/viewer.mjs:1398:15
setDocument@http://127.0.0.1:35021/build/generic/web/viewer.mjs:12172:21
close@http://127.0.0.1:35021/build/generic/web/viewer.mjs:15563:22
testingClose@http://127.0.0.1:35021/build/generic/web/viewer.mjs:16357:51
```

Author: calixteman

web/app.js

@@ -1048,7 +1048,7 @@ const PDFViewerApplication = {
       this.pdfDocument = null;
 
       this.pdfThumbnailViewer?.setDocument(null);
-      this.pdfViewer.setDocument(null);
+      await this.pdfViewer.setDocument(null);
       this.pdfLinkService.setDocument(null);
       this.pdfDocumentProperties?.setDocument(null);
     }