fix: Prepares for IPooledEnumerable removal (#1548)

### Summary

- Removes `IPooledEnumerable` (non-generic)
- Changes `IPooledEnumerable<T>` so that  `Free()` is replaced with the `IDisposable` pattern

Projects/UOContent/Engines/Doom/LeverPuzzle/LeverPuzzleController.cs

@@ -203,14 +203,11 @@ public partial class LeverPuzzleController : Item
         {
             if (item is LeverPuzzleController)
             {
-                eable.Free();
                 e.Mobile.SendMessage("Lamp room puzzle already exists: please delete the existing controller first ...");
                 return;
             }
         }
 
-        eable.Free();
-
         e.Mobile.SendMessage("Generating Lamp Room puzzle...");
 
         NetState.FlushAll();
@@ -533,8 +530,6 @@ public partial class LeverPuzzleController : Item
 
             state.Send(buffer);
         }
-
-        eable.Free();
     }
 
     private void Deserialize(IGenericReader reader, int version)
@@ -620,7 +615,6 @@ public partial class LeverPuzzleController : Item
                         var eable = m_IEntity.Map.GetMobilesInRange(m_IEntity.Location, 2);
                         var mobiles = new List<Mobile>();
                         mobiles.AddRange(eable);
-                        eable.Free();
 
                         for (var k = 0; k < mobiles.Count; k++)
                         {