use index from gameobject to set set temp mods

MareSynchronos/Utils/VariousExtensions.cs

@@ -1,4 +1,5 @@
-using System.Text.Json;
+using Dalamud.Game.ClientState.Objects.Types;
+using System.Text.Json;
 
 namespace MareSynchronos.Utils;
 
@@ -8,4 +9,14 @@ public static class VariousExtensions
     {
         return JsonSerializer.Deserialize<T>(JsonSerializer.Serialize(obj))!;
     }
+
+    public static unsafe int? ObjectTableIndex(this GameObject? gameObject)
+    {
+        if (gameObject == null || gameObject.Address == IntPtr.Zero)
+        {
+            return null;
+        }
+
+        return ((FFXIVClientStructs.FFXIV.Client.Game.Object.GameObject*)gameObject.Address)->ObjectIndex;
+    }
 }