Apply suggestions from code review

Co-authored-by: Cody Robibero <cody@robibe.ro>

Jellyfin.Server.Implementations/Events/Consumers/Session/PlaybackStartLogger.cs

@@ -67,7 +67,7 @@ namespace Jellyfin.Server.Implementations.Events.Consumers.Session
                 GetPlaybackNotificationType(eventArgs.MediaInfo.MediaType),
                 user.Id)
             {
-                ItemId = eventArgs.Item?.Id.ToString()
+                ItemId = eventArgs.Item?.Id.ToString("N", CultureInfo.InvariantCulture),
             })
             .ConfigureAwait(false);
         }

Jellyfin.Server.Implementations/Events/Consumers/Session/PlaybackStopLogger.cs

@@ -75,7 +75,7 @@ namespace Jellyfin.Server.Implementations.Events.Consumers.Session
                     notificationType,
                     user.Id)
                 {
-                    ItemId = eventArgs.Item?.Id.ToString()
+                    ItemId = eventArgs.Item?.Id.ToString("N", CultureInfo.InvariantCulture),
                 })
                 .ConfigureAwait(false);
         }