docker/attacker/Dockerfile: mongosh download fails with exit code 133

### When building the `goe-attacker` image, the mongosh install step fails:
```The command 'wget -q "https://downloads.mongodb.com/compass/mongosh-2.3.1-linux-x64.tgz"...' returned non-zero code: 133```

Tried bumping to 2.3.8, same result.
Only affects scenarios using MongoDB atoms (mongodb_disable_auth, database_expose).

### Workaround: comment out the mongosh block. 