Remove SpreaderNodeGroup (#20230)

* Remove SpreaderNodeGroup

* Fix airtight updates

* more smoke stuff

* more smoke fixes

* wtf is smoke code

* Fix merge

* Fix divide by zero

Content.Server/Spreader/GrowingKudzuComponent.cs

@@ -5,12 +5,6 @@ namespace Content.Server.Spreader;
 [RegisterComponent, Access(typeof(KudzuSystem))]
 public sealed partial class GrowingKudzuComponent : Component
 {
-    /// <summary>
-    /// At level 3 spreading can occur; prior to that we have a chance of increasing our growth level and changing our sprite.
-    /// </summary>
-    [DataField("growthLevel")]
-    public int GrowthLevel = 1;
-
     /// <summary>
     /// The next time kudzu will try to tick its growth level.
     /// </summary>