Ensure that the password dialog is always closed with the document

If the current PDF document is closed while the password dialog is open, e.g. manually by calling `PDFViewerApplication.close()` from the console, the password dialog wouldn't be closed as intended.

*Please note:* This could only affect the GENERIC viewer, although it's very unlikely to ever happen, since that's the only one that supports opening more than one PDF document.

web/app.js

@@ -1005,7 +1005,10 @@ const PDFViewerApplication = {
     this._saveInProgress = false;
     this._hasAnnotationEditors = false;
 
-    promises.push(this.pdfScriptingManager.destroyPromise);
+    promises.push(
+      this.pdfScriptingManager.destroyPromise,
+      this.passwordPrompt.close()
+    );
 
     this.setTitle();
     this.pdfSidebar?.reset();