Mobs still count towards the mob cap during their death animation

The bug

While a mob is dying it still counts towards the mob cap.

To reproduce

1. /gamerule doMobSpawning false
2. Set difficulty to peaceful
3. Set difficulty back to another difficulty
4. Open F3 and observe the line starting with "SC"
5. Summon a husk
   → The "M" value increases by 1, indicating that the mob cap for hostile mobs increased by 1
6. Kill the husk
   → The "M" value doesn't decrease again until the death animation stops