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/Harvest/Core/HarvestSystem.cs

@@ -312,13 +312,10 @@ namespace Server.Engines.Harvest
             {
                 if (i.StackWith(m, i, false))
                 {
-                    eable.Free();
                     return true;
                 }
             }
 
-            eable.Free();
-
             item.MoveToWorld(m.Location, map);
             return true;
         }