Improve ingame moderation for admins (#3678)

## Description:

Players with the `admin` flare can now kick players from any game
(including public lobbies), not just the lobby creator in private
lobbies.

## 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

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

w.o.n

src/server/Client.ts

@@ -14,7 +14,7 @@ export class Client {
     public readonly clientID: ClientID,
     public readonly persistentID: string,
     public readonly claims: TokenPayload | null,
-    public readonly roles: string[] | undefined,
+    public readonly role: string | null,
     public readonly flares: string[] | undefined,
     public readonly ip: string,
     public username: string,