Warden doesn't detect non-player mobs colliding with them

The Bug:
The Warden will attack every Mob in the game. If if the Warden receives too many vibrations from any mob, it will kill it. However, the Warden's collision only detects players, not all mobs.

Steps to Reproduce:

• Create a small 4x4 area so the mobs can't travel far
• Summon a few Zombies in the 4x4 area
• Summon a Warden in the 4x4 area
• Wait for the Zombies to collide with the Warden

Observed Result:
The Warden doesn't get angry when the mobs collide with it
The Warden only gets angry from vibrations and when sniffing the same mob after 3-4 sniffs

Expected Result:
The Warden will get angry from mobs that collide with it.