Fix Websocket OpenApi (#9935)

* Further split inbound and outbound messages

* Fix datatype for inbound start messages

* fixes from review

MediaBrowser.Controller/Net/WebSocketMessages/InboundWebSocketMessageOfT.cs

@@ -0,0 +1,26 @@
+#pragma warning disable SA1649 // File name must equal class name.
+
+namespace MediaBrowser.Controller.Net.WebSocketMessages;
+
+/// <summary>
+/// Inbound websocket message with data.
+/// </summary>
+/// <typeparam name="T">The data type.</typeparam>
+public class InboundWebSocketMessage<T> : WebSocketMessage<T>, IInboundWebSocketMessage
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="InboundWebSocketMessage{T}"/> class.
+    /// </summary>
+    public InboundWebSocketMessage()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="InboundWebSocketMessage{T}"/> class.
+    /// </summary>
+    /// <param name="data">The data to send.</param>
+    protected InboundWebSocketMessage(T data)
+    {
+        Data = data;
+    }
+}