fix: Changes Map.Sector.Mobiles to link list & Fixes various related crash bugs (#1553)

### Summary

Eliminates `IPooledEnumerable<T>` and `eable.Free()` from `Map` for mobiles. This drastically simplifies code that iterates in range, for example:

```cs
foreach (var m in m.GetMobilesInRange(5))
{
}
```
The code above no longer requires an eable and calling `Free()`.

- [X] Fixed several locations where an NPC that was damaged would cause a server crash.
- [X] Removed an unnecessary allocation in guard fake calls (NPCs calling guards on you)
- [X] Fixes damage precision loss in Poison Strike Spell
- [X] BogThing no longer attempts to "search" for boglings to eat when it is at full health

Projects/UOContent/Multis/Houses/HousePlacement.cs

@@ -151,12 +151,8 @@ namespace Server.Multis
 
                     mobiles.Clear();
 
-                    var sector = map.GetSector(tileX, tileY);
-
-                    for (var i = 0; i < sector.Mobiles.Count; ++i)
+                    foreach (var m in map.GetMobilesAt(tileX, tileY))
                     {
-                        var m = sector.Mobiles[i];
-
                         if (m.X == tileX && m.Y == tileY)
                         {
                             mobiles.Add(m);