Replaces PowerReceiver's C# event with a ComponentMessage (#2888)

Co-authored-by: py01 <pyronetics01@gmail.com>

Content.Server/GameObjects/Components/Chemistry/ReagentDispenserComponent.cs

@@ -1,4 +1,4 @@
-#nullable enable
+#nullable enable
 using System;
 using System.Linq;
 using System.Threading.Tasks;
@@ -83,15 +83,21 @@ namespace Content.Server.GameObjects.Components.Chemistry
             _beakerContainer =
                 ContainerManagerComponent.Ensure<ContainerSlot>($"{Name}-reagentContainerContainer", Owner);
 
-            if (Owner.TryGetComponent(out PowerReceiverComponent? receiver))
-            {
-                receiver.OnPowerStateChanged += OnPowerChanged;
-            }
-
             InitializeFromPrototype();
             UpdateUserInterface();
         }
 
+        public override void HandleMessage(ComponentMessage message, IComponent? component)
+        {
+            base.HandleMessage(message, component);
+            switch (message)
+            {
+                case PowerChangedMessage powerChanged:
+                    OnPowerChanged(powerChanged);
+                    break;
+            }
+        }
+
         /// <summary>
         /// Checks to see if the <c>pack</c> defined in this components yaml prototype
         /// exists. If so, it fills the reagent inventory list.
@@ -111,7 +117,7 @@ namespace Content.Server.GameObjects.Components.Chemistry
             }
         }
 
-        private void OnPowerChanged(object? sender, PowerStateEventArgs e)
+        private void OnPowerChanged(PowerChangedMessage e)
         {
             UpdateUserInterface();
         }