Fix: U4-5180 Notifications email highlighting is incorrect. Ensured the versions of content used in comparison is sorted correctly so the highlighting is based on previous version and not the base version of the content.

src/Umbraco.Core/Services/NotificationService.cs

@@ -204,6 +204,8 @@ namespace Umbraco.Core.Services
             if (createSubject == null) throw new ArgumentNullException("createSubject");
             if (createBody == null) throw new ArgumentNullException("createBody");
 
+            allVersions = allVersions.OrderBy(x => x.UpdateDate).ToArray();
+
             int versionCount = (allVersions.Length > 1) ? (allVersions.Length - 2) : (allVersions.Length - 1);
             var oldDoc = _contentService.GetByVersion(allVersions[versionCount].Version);