Bug 1935073 - Fix sort indicator in "Search Messages" window. r=john.bieling

Differential Revision: https://phabricator.services.mozilla.com/D231169

--HG--
extra : moz-landing-system : lando

mail/base/content/folderDisplay.js

@@ -567,8 +567,8 @@ FolderDisplayWidget.prototype = {
   _updateThreadDisplay() {
     if (this.view.dbView) {
       UpdateSortIndicators(
-        this.view.dbView.sortType,
-        this.view.dbView.sortOrder
+        this.view.primarySortColumnId,
+        this.view.primarySortOrder
       );
       SetNewsFolderColumns();
       UpdateSelectCol();