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/Items/Skill Items/Misc/FireHorn.cs

@@ -98,10 +98,9 @@ public partial class FireHorn : Item
         );
 
         var playerVsPlayer = false;
-        var eable = from.Map.GetMobilesInRange(loc, 2);
 
         using var targets = PooledRefQueue<Mobile>.Create();
-        foreach (var m in eable)
+        foreach (var m in from.Map.GetMobilesInRange(loc, 2))
         {
             if (from != m && SpellHelper.ValidIndirectTarget(from, m) && from.CanBeHarmful(m, false) &&
                 (!Core.AOS || from.InLOS(m)))