Private lobby toggle donation (#1752)

## Description:
Resolve #1652 

1. Add the ability to toggle **gold donations** and **troop donations**
for private lobbies
~2. Add relevant translations.~
3. Refactor `canDonate` to be specific to gold and troop donations 
4. Add placeholders for singleplayer mode if this is to be extended to
support that too.
5. Add Tests for Donate logic

### Screenshots:
<img width="1643" height="1788" alt="image"
src="https://github.com/user-attachments/assets/82b93400-a1f0-45f0-8b2b-a7f78dc0c3e9"
/>

_Private Lobby_

### Smoke Tests


![donatetroopsprivatelobby](https://github.com/user-attachments/assets/c6690bbc-958e-48a1-9cf1-e2b361dfb1b2)
_Testing Troop Send In Private Lobby_


![donatetroopsprivatelobby2](https://github.com/user-attachments/assets/698c7603-6b4b-4da7-91ab-7bdc38bb49a5)

_Troop Send Complete In Private Lobby_


![testtradepublicteams](https://github.com/user-attachments/assets/1010332c-3f38-4644-9218-46aa7141f578)
Confirming that public teams still works


## 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 have read and accepted the CLA agreement (only required once).

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

DISCORD_USERNAME: cool_clarky

---------

Co-authored-by: Scott Anderson <662325+scottanderson@users.noreply.github.com>
Co-authored-by: Drills Kibo <59177241+drillskibo@users.noreply.github.com>

src/client/SinglePlayerModal.ts

@@ -37,7 +37,9 @@ export class SinglePlayerModal extends LitElement {
   @state() private disableNPCs: boolean = false;
   @state() private bots: number = 400;
   @state() private infiniteGold: boolean = false;
+  @state() private donateGold: boolean = false;
   @state() private infiniteTroops: boolean = false;
+  @state() private donateTroops: boolean = false;
   @state() private instantBuild: boolean = false;
   @state() private useRandomMap: boolean = false;
   @state() private gameMode: GameMode = GameMode.FFA;
@@ -451,7 +453,9 @@ export class SinglePlayerModal extends LitElement {
               disableNPCs: this.disableNPCs,
               bots: this.bots,
               infiniteGold: this.infiniteGold,
+              donateGold: this.donateGold,
               infiniteTroops: this.infiniteTroops,
+              donateTroops: this.donateTroops,
               instantBuild: this.instantBuild,
               disabledUnits: this.disabledUnits
                 .map((u) => Object.values(UnitType).find((ut) => ut === u))