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/Pathing/Movement.cs

@@ -22,7 +22,7 @@ namespace Server.Movement
 
         private readonly List<Item>[] _pools = { new(), new(), new(), new() };
 
-        private readonly HashSet<Sector> _sectors = new();
+        private readonly HashSet<Map.Sector> _sectors = new();
 
         private MovementImpl()
         {