Downed Vendors Completely Covering Barricades

### Testmerges

#5086, #5337, #5228, #5007, #5407, #5435

### Round ID

_No response_

### Description of the bug

Vendors knocked down seem to overlay on top of barricades rendering the barricade completely invisible to people trying to move into the tile occupied by the downed vendor/barricade.

Vendor covering the barricade with pointer arrow indicating the vendor/barricade:

Vendor/barricade tile contents:

### What's the difference with what should have happened?

Barricades impede movement and should be visible regardless of some other object being on top of it to make for fair and easy travel around those barricades.

### How do we reproduce this bug?

1. Make barricade(in the picture's case facing up).
2. Move or spawn vendor onto the tile the barricade occupies.
3. Knock down the vendor(xenos can do this by using grab intent on the vendor with an empty hand but explosions work too.)
4. Observe the barricade.
5. Fail to see the barricade.

### Issue Bingo

- [X] Issue could be reproduced at least once
- [X] Issue happened in a recent (less than 7 days ago) round
- [X] Couldn't find an existing issue about this (https://github.com/cmss13-devs/cmss13/issues)