fix: Removes GetObjectsInRange and fixes boat planks closing (#1579)

## BREAKING CHANGE

- Deletes `map.GetObjectsInRange` and `map.GetObejctsInBounds`

### Notes

Developers are expected to enumerate mobiles and items separately now using `map.GetMobilesInRange` and `map.GetItemsInRange`. This helps keep the code streamlined so we don't have to maintain multiple copies of ref struct enumerators that do the same thing.


### Fixes

- [X] Fixes bug with planks closing
- [X] Fixes issue with iterating items/mobiles from a null map

Projects/Server/Maps/Map.MobileEnumerator.cs

@@ -21,6 +21,9 @@ namespace Server;
 
 public partial class Map
 {
+    private static ValueLinkList<Mobile> _emptyMobileLinkList = new();
+    public static ref readonly ValueLinkList<Mobile> EmptyMobileLinkList => ref _emptyMobileLinkList;
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public MobileAtEnumerable<Mobile> GetMobilesAt(Point3D p) => GetMobilesAt<Mobile>(p);
 
@@ -110,7 +113,14 @@ public partial class Map
         {
             _started = false;
             _location = loc;
-            _linkList = ref map.GetRealSector(loc.m_X, loc.m_Y).Mobiles;
+            if (map == null)
+            {
+                _linkList = ref EmptyMobileLinkList;
+            }
+            else
+            {
+                _linkList = ref map.GetRealSector(loc.m_X, loc.m_Y).Mobiles;
+            }
             _version = 0;
             _current = null;
         }