Restore NetworkMessageDirection enum

Fixes API breakage

Dalamud/Game/Network/NetworkMessageDirection.cs

@@ -0,0 +1,18 @@
+namespace Dalamud.Game.Network;
+
+/// <summary>
+/// This represents the direction of a network message.
+/// </summary>
+[Obsolete("No longer part of public API", true)]
+public enum NetworkMessageDirection
+{
+    /// <summary>
+    /// A zone down message.
+    /// </summary>
+    ZoneDown,
+
+    /// <summary>
+    /// A zone up message.
+    /// </summary>
+    ZoneUp,
+}