Monsters that cast spells on death have two death entries in the log.

### Describe the bug

Any monster that casts a spell when it dies will die twice, at least according to the message log.

### Steps to reproduce

1. Spawn or locate a zombie that casts a spell on death. Zombie children are a great example
2. Kill them
3. "The zombie child dies x2!"

### Expected behavior

Only one entry in the log per death.

### Screenshots


### Versions and configuration

- OS: Windows
- OS Version: 10.0.19044.1826 (21H2)
- Game Version: d6a1777 [64-bit]
- Graphics Version: Tiles
- Game Language: System language []
- Mods loaded: [
Dark Days Ahead [dda],
Disable NPC Needs [no_npc_food],
No Fungal Growth [no_fungal_growth],
Bionic Professions [package_bionic_professions],
No Rail Stations [No_Rail_Stations],
No Vault [No_Vault],
ASCIITiles overmap color fix [colors_fix_asciitiles]
]

### Additional context

Discovered while trying to fix #59054. This is a separate and unrelated issue.

Reproduce the issue by killing a zombie child or another monster that casts a spell on death, then trace the code paths responsible for the death messages and spell-on-death behavior. Done means the message log contains one death entry per monster death while the spell still occurs.

Written by the indexing model from the issue text.