Fix SyncPlay WebSocket OpenAPI schemas (#13946)

MediaBrowser.Model/SyncPlay/SyncPlayUserLeftUpdate.cs

@@ -0,0 +1,21 @@
+using System;
+using System.ComponentModel;
+
+namespace MediaBrowser.Model.SyncPlay;
+
+/// <inheritdoc />
+public class SyncPlayUserLeftUpdate : GroupUpdate<string>
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SyncPlayUserLeftUpdate"/> class.
+    /// </summary>
+    /// <param name="groupId">The groupId.</param>
+    /// <param name="data">The data.</param>
+    public SyncPlayUserLeftUpdate(Guid groupId, string data) : base(groupId, data)
+    {
+    }
+
+    /// <inheritdoc />
+    [DefaultValue(GroupUpdateType.UserLeft)]
+    public override GroupUpdateType Type => GroupUpdateType.UserLeft;
+}