Destructible spawning fix redux (#2892)

* Fix SpawnEntitiesBehavior crash and add test

* Fix comparer, add duplicated behavior

Turns out this isn't Java

* Threshold behaviors are now "linearly" executed

* Fixes YAML threshold behaviors to be linear

Co-authored-by: DrSmugleaf <DrSmugleaf@users.noreply.github.com>

Content.Server/GameObjects/Components/Destructible/Thresholds/Behavior/IThresholdBehavior.cs

@@ -6,6 +6,14 @@ namespace Content.Server.GameObjects.Components.Destructible.Thresholds.Behavior
 {
     public interface IThresholdBehavior : IExposeData
     {
+        /// <summary>
+        ///     Triggers this behavior.
+        /// </summary>
+        /// <param name="owner">The entity that owns this behavior.</param>
+        /// <param name="system">
+        ///     An instance of <see cref="DestructibleSystem"/> to pull dependencies
+        ///     and other systems from.
+        /// </param>
         void Trigger(IEntity owner, DestructibleSystem system);
     }
 }