Fix publish status with invarint case insensative culture check

Author: bergmania

src/Umbraco.Core/Services/PublishStatus/PublishStatusService.cs

@@ -46,7 +46,7 @@ public bool IsDocumentPublished(Guid documentKey, string culture)
     {
         if (_publishedCultures.TryGetValue(documentKey, out ISet<string>? publishedCultures))
         {
-            return publishedCultures.Contains(culture);
+            return publishedCultures.Contains(culture, StringComparer.InvariantCultureIgnoreCase);
         }
 
         _logger.LogDebug("Document {DocumentKey} not found in the publish status cache", documentKey);