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/Mobiles/BaseCreature.cs

@@ -3649,8 +3649,6 @@ namespace Server.Mobiles
                 }
             }
 
-            eable.Free();
-
             if (toRummage == null)
             {
                 return false;
@@ -3813,7 +3811,6 @@ namespace Server.Mobiles
                     queue.Enqueue(pet);
                 }
             }
-            eable.Free();
 
             while (queue.Count > 0)
             {
@@ -5360,7 +5357,6 @@ namespace Server.Mobiles
                     queue.Enqueue(m);
                 }
             }
-            eable.Free();
 
             while (queue.Count > 0)
             {