US Army Synthetic is missing the background color for its tacmap and orbit menu icon.

### Testmerges

#10925, #12947, #12627, #12967, #13037, #13143

### Round ID

36394

### Description of the bug

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

It should probably share the background color with the rest of the US Army dudes.

### How do we reproduce this bug?

1. Roll as synth survivor on Tyrargo.
2. Observe the tacmap and orbit menu.

### 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)

Reproduce the issue by rolling as a synth survivor on Tyrargo and observing the tacmap and orbit menu. Find the background-color definitions for those UI elements, compare them with the other US Army characters, and verify that both use the expected shared color.

Written by the indexing model from the issue text.