Mobs do not avoid fall damage while chasing target

The bug

When the mob chasing a target at high place, it will walk down directly and get fall damage, this bug is only affects when mobs chasing a target, not affects when the mob is doing other something else (such as piglins find gold ingot, villagers find bed and work station).

Step to reproduce

1. Building a 6 blocks tall pillar
2. Building a downward stairway to the side of pillar
3. Summoning a zombie on the pillar
4. Let the zombie attacking you.

-->  The zombie walked down directly and took fall damage rather than walked on stair.