The game crashes if you set the wrong search criterion in the window for changing the shape of vehicle parts

### Describe the bug

Pressing enter will crash the game

If you type in the correct criteria (front or fr), no crashes.

### Attach save file

[test-trimmed.tar.gz](https://github.com/user-attachments/files/18466270/test-trimmed.tar.gz)
[crash.log](https://github.com/user-attachments/files/18466291/crash.log)

### Steps to reproduce

1. Standard world and character
2. Spawn any car
3. `E`xamine the vehicle and choose to change the sha`p`e of any part (I changed the shape of the door)
4. press `/` and type `front`
5. Verify that there is no crash
6. Change the prompt to a meaningless set of letters (`123` or `kkk`)
7. Get a crash from the game

### Expected behavior

n/a

### Screenshots

_No response_

### Versions and configuration
The game is run through an emulator.

- OS: Windows
- OS Version: 10.0.19043 (21H1)
- Game Version: 018223c [64-bit]
- Graphics Version: Tiles
- Game Language: English [en]
- Mods loaded: [
Dark Days Ahead [dda],
Disable NPC Needs [no_npc_food],
Portal Storms Ignore NPCs [personal_portal_storms],
Slowdown Fungal Growth [no_fungal_growth]
]

### Additional context

It does not reproduce on version 0.H

Start with crash.log and test-trimmed.tar.gz, then reproduce the crash by following the listed vehicle-part shape search steps in the game. Trace the invalid search criterion from that interaction and verify that meaningless input no longer crashes while valid criteria such as “front” still work.

Written by the indexing model from the issue text.