Disable trains in public games (#1342)

## Description:

1. Disable trains in public games
2. add more checks so people can't build trains by bypass the UI.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

src/server/MapPlaylist.ts

@@ -1,5 +1,11 @@
 import { getServerConfigFromServer } from "../core/configuration/ConfigLoader";
-import { Difficulty, GameMapType, GameMode, GameType } from "../core/game/Game";
+import {
+  Difficulty,
+  GameMapType,
+  GameMode,
+  GameType,
+  UnitType,
+} from "../core/game/Game";
 import { PseudoRandom } from "../core/PseudoRandom";
 import { GameConfig } from "../core/Schemas";
 import { logger } from "./Logger";
@@ -61,6 +67,7 @@ export class MapPlaylist {
       gameMode: mode,
       playerTeams: numPlayerTeams,
       bots: 400,
+      disabledUnits: [UnitType.Train, UnitType.Factory],
     } satisfies GameConfig;
   }