Navalis - You can paradrop out of bounds

### Testmerges

N/A

### Round ID

N/A

### Description of the bug

Title.
I.E. You toss a signal flare out onto the monorial, the GP locks that, and you paradrop onto it, but you're out of bounds.

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

No dropping here

### How do we reproduce this bug?

1. Have someone toss a signal flare in a place you definitely should get dropped.
2. Paradrop onto it.
3. Be stuck
...

### 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)