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/Spells/Seventh/ChainLightning.cs

@@ -35,11 +35,9 @@ namespace Server.Spells.Seventh
 
                 if (map != null)
                 {
-                    using var pool = PooledRefQueue<Mobile>.Create();
                     var pvp = false;
-
-                    var eable = map.GetMobilesInRange(loc, 2);
-                    foreach (var m in eable)
+                    using var pool = PooledRefQueue<Mobile>.Create();
+                    foreach (var m in map.GetMobilesInRange(loc, 2))
                     {
                         if (Core.AOS && (m == Caster || !Caster.InLOS(m)) ||
                             !SpellHelper.ValidIndirectTarget(Caster, m) ||