Core/Maps: Use a fixed offset instead of full collision height when retrieving floor Z

Port From (https://github.com/TrinityCore/TrinityCore/commit/9bcff210f90d57689557b7b8cc20cd336b8ab035)

Source/Framework/Constants/MapConst.cs

@@ -56,6 +56,7 @@ namespace Framework.Constants
         public const float MaxHeight = 100000.0f;
         public const float MaxFallDistance = 250000.0f;
         public const float GroundHeightTolerance = 0.05f;
+        public const float ZOffsetFindHeight = 0.5f;
         public const float DefaultCollesionHeight = 2.03128f; // Most common value in dbc
 
         public const uint MapMagic = 0x5350414D; //"MAPS";

Source/Game/Entities/Object/WorldObject.cs

@@ -3601,7 +3601,7 @@ namespace Game.Entities
         {
             if (!IsInWorld)
                 return m_staticFloorZ;
-            return Math.Max(m_staticFloorZ, GetMap().GetGameObjectFloor(GetPhaseShift(), GetPositionX(), GetPositionY(), GetPositionZ() + GetCollisionHeight()));
+            return Math.Max(m_staticFloorZ, GetMap().GetGameObjectFloor(GetPhaseShift(), GetPositionX(), GetPositionY(), GetPositionZ() + MapConst.ZOffsetFindHeight));
         }
 
         public float GetMapWaterOrGroundLevel(float x, float y, float z)
@@ -3618,7 +3618,7 @@ namespace Game.Entities
         public float GetMapHeight(float x, float y, float z, bool vmap = true, float distanceToSearch = MapConst.DefaultHeightSearch)
         {
             if (z != MapConst.MaxHeight)
-                z += GetCollisionHeight();
+                z += MapConst.ZOffsetFindHeight;
 
             return GetMap().GetHeight(GetPhaseShift(), x, y, z, vmap, distanceToSearch);
         }

Source/Game/Maps/Map.cs

@@ -1731,7 +1731,7 @@ namespace Game.Maps
             if (GetGridMap(PhasingHandler.GetTerrainMapId(phaseShift, this, x, y), x, y) != null)
             {
                 // we need ground level (including grid height version) for proper return water level in point
-                float ground_z = GetHeight(phaseShift, x, y, z + collisionHeight, true, 50.0f);
+                float ground_z = GetHeight(phaseShift, x, y, z + MapConst.ZOffsetFindHeight, true, 50.0f);
                 ground = ground_z;
 
                 LiquidData liquid_status;