fix: client DC when empty Input Variable event is sent (#2781)

Fixes #2765

Author: Arufonsu

Intersect.Server.Core/Entities/Player.cs

@@ -6980,8 +6980,9 @@ public void RespondToEventInput(Guid eventId, bool newValueBool, int newValue, s
 
                                     break;
                                 case VariableDataType.String:
-                                    if (newValueString.Length >= cmd.Minimum &&
-                                        newValueString.Length <= cmd.Maximum)
+                                    var stringValue = newValueString ?? string.Empty;
+                                    var stringLength = stringValue.Length;
+                                    if (stringLength >= cmd.Minimum && stringLength <= cmd.Maximum)
                                     {
                                         if (value.String != newValueString)
                                         {

Intersect.Server.Core/Networking/PacketHandler.cs

@@ -1468,11 +1468,13 @@ public void HandlePacket(Client client, EventResponsePacket packet)
     //EventInputVariablePacket
     public void HandlePacket(Client client, EventInputVariablePacket packet)
     {
-        client.Entity.RespondToEventInput(
+        var player = client?.Entity;
+
+        player?.RespondToEventInput(
             packet.EventId,
             packet.BooleanValue,
             packet.Value,
-            packet.StringValue,
+            packet.StringValue ?? string.Empty,
             packet.Canceled
         );
     }