Core/Movement: Fix LoS issue of NPCs chasing targets

Port From (https://github.com/TrinityCore/TrinityCore/commit/f012d4b7fcf0376de75f09c2b59509247fd133cb)

Source/Game/Movement/Generators/ChaseMovementGenerator.cs

@@ -259,7 +259,11 @@ namespace Game.Movement
                 return false;
             if (maxDistance.HasValue && distSq > MathF.Sqrt(maxDistance.Value))
                 return false;
-            return !angle.HasValue || angle.Value.IsAngleOkay(target.GetRelativeAngle(owner));
+            if (angle.HasValue && !angle.Value.IsAngleOkay(target.GetRelativeAngle(owner)))
+                return false;
+            if (!owner.IsWithinLOSInMap(target))
+                return false;
+            return true;
         }
 
         static void DoMovementInform(Unit owner, Unit target)

Source/Game/Movement/Generators/PathGenerator.cs

@@ -892,6 +892,10 @@ namespace Game.Movement
                 return;
 
             int i = _pathPoints.Length - 1;
+            float x;
+            float y;
+            float z;
+            float collisionHeight = _sourceUnit.GetCollisionHeight();
             // find the first i s.t.:
             //  - _pathPoints[i] is still too close
             //  - _pathPoints[i-1] is too far away
@@ -902,6 +906,15 @@ namespace Game.Movement
                 if ((_pathPoints[i - 1] - target).LengthSquared() >= distSq)
                     break; // bingo!
 
+                // check if the shortened path is still in LoS with the target
+                _sourceUnit.GetHitSpherePointFor(new Position(_pathPoints[i - 1].X, _pathPoints[i - 1].Y, _pathPoints[i - 1].Z + collisionHeight), out x, out y, out z);
+                if (!_sourceUnit.GetMap().IsInLineOfSight(_sourceUnit.GetPhaseShift(), x, y, z, _pathPoints[i - 1].X, _pathPoints[i - 1].Y, _pathPoints[i - 1].Z + collisionHeight, LineOfSightChecks.All, ModelIgnoreFlags.Nothing))
+                {
+                    // whenver we find a point that is not in LoS anymore, simply use last valid path
+                    Array.Resize(ref _pathPoints, i + 1);
+                    return;
+                }
+
                 if (--i == 0)
                 {
                     // no point found that fulfills the condition