fix(Core/Movement) Smoother movement of hunter pets when following players (#16796)

* Pets follow the player at the player's speed

* More accurate distance measurement

src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp

@@ -303,29 +303,15 @@ static Optional<float> GetVelocity(Unit* owner, Unit* target, G3D::Vector3 const
         }
 
         UnitMoveType moveType = Movement::SelectSpeedType(moveFlags);
-        speed = std::max(target->GetSpeed(moveType), owner->GetSpeed(moveType));
+        speed = target->GetSpeed(moveType);
-
         if (playerPet)
         {
-            float distance = owner->GetDistance2d(dest.x, dest.y) - (*speed / 2.f);
+            float distance = owner->GetDistance2d(dest.x, dest.y) - target->GetObjectSize() - (*speed / 2.f);
             if (distance > 0.f)
             {
                 float multiplier = 1.f + (distance / 10.f);
                 *speed *= multiplier;
             }
-            else
-            {
-                switch (moveType)
-                {
-                    case MOVE_RUN_BACK:
-                    case MOVE_SWIM_BACK:
-                    case MOVE_FLIGHT_BACK:
-                        break;
-                    default:
-                        *speed *= 0.9f;
-                        break;
-                }
-            }
         }
     }