Explosives with timers now properly alert admins when detonating (#40471)

* Explosives with timers now properly alert admins when detonating

* add TODO comment

* Check if user is deleted before triggering

Content.Shared/Trigger/Components/TimerTriggerComponent.cs

@@ -75,6 +75,7 @@ public sealed partial class TimerTriggerComponent : Component
 
     /// <summary>
     /// The entity that activated this trigger.
+    /// TODO: use WeakEntityReference once the engine PR is merged!
     /// </summary>
     [DataField, AutoNetworkedField]
     public EntityUid? User;