Throttle MagicMirror do_afters (#23867)

Doesn't fix the gross network spam but that's for later.

Content.Server/MagicMirror/MagicMirrorComponent.cs

@@ -1,3 +1,4 @@
+using Content.Shared.DoAfter;
 using Content.Shared.Humanoid;
 using Robust.Shared.Audio;
 
@@ -9,6 +10,9 @@ namespace Content.Server.MagicMirror;
 [RegisterComponent]
 public sealed partial class MagicMirrorComponent : Component
 {
+    [DataField]
+    public DoAfterId? DoAfter;
+
     /// <summary>
     /// Magic mirror target, used for validating UI messages.
     /// </summary>