Iron golems are knocked back by explosions

The bug

Iron golems are immune to knockback. However, they are still knocked back by explosions. In general, this is an issue with any mob with the knockback_resistance component.

How to reproduce

1. Spawn an iron golem
2. Hit it with a sword
   →  No knockback (even if the sword is enchanted with knockback)
3. Spawn and ignite a creeper
   →  After it explodes, the golem is knocked back