fix: Fixes null components in BaseAddon (#2208)

Projects/UOContent/Items/Addons/AddonComponent.cs

@@ -104,7 +104,7 @@ namespace Server.Items
         }
 
         [SerializableField(0)]
-        [SerializedCommandProperty(AccessLevel.GameMaster)]
+        [SerializedCommandProperty(AccessLevel.GameMaster, readOnly: true)]
         public BaseAddon _addon;
 
         [SerializableField(1)]

Projects/UOContent/Items/Addons/BaseAddon.cs

@@ -270,7 +270,8 @@ namespace Server.Items
 
             foreach (var c in Components)
             {
-                c.Delete();
+                // Component can become null if the Addon property is somehow deleted, then the component itself is deleted.
+                c?.Delete();
             }
         }
 
@@ -283,5 +284,12 @@ namespace Server.Items
                 _resource = (CraftResource)reader.ReadEncodedInt();
             }
         }
+
+        [AfterDeserialization]
+        private void AfterDeserialization()
+        {
+            // We have had issues in the past, so let's tidy it up.
+            _components?.Tidy();
+        }
     }
 }