van is not slowed by water

## Testmerges
#9894: 'Multiz indicator' by Detective-Google at commit 5dbc10a0d2
#7093: 'creates ipcheck subsystem' by hry-gh at commit 2a3e40559b
#10340: 'New on_mobs for splints, bandages and blood overlays (Other changes to blood included)' by LC4492 at commit 14a671a4e4
#9774: 'Adds a minesweeper game to a bunch of interactions.' by kiVts at commit c403ea053f
#8963: 'Ports tacmap port from PVE' by Git-Nivrak at commit b2dced9d85
#10751: 'stairs up' by cuberound at commit 33618b636c

## Round ID
30242

## Description of the bug
title

## What's the difference with what should have happened?
bugs slowed by water. van not slowed by water. survivors no killable

## How do we reproduce this bug?
1) get in van
2) drive on water

## Attached logs
```
N/A
```

## Additional details
- Author: Vending Machine
- Admin: Vending Machine
- Note: None

No files or tests are named. Reproduce the issue by entering a van and driving it onto water, then compare its movement with other vehicles that are slowed by water. Done means the van is slowed by water as expected.

Written by the indexing model from the issue text.