Stop match before starting a new one

Author: VirxEC

RLBotCS/Server/ServerMessage/StartMatch.cs

@@ -12,6 +12,7 @@ public ServerAction Execute(ServerContext context)
         Debug.Assert(ConfigValidator.Validate(MatchConfig));
 
         context.Bridge.TryWrite(new ClearRenders());
+        context.Bridge.TryWrite(new EndMatch());
 
         foreach (var (writer, _) in context.Sessions.Values)
             writer.TryWrite(new SessionMessage.StopMatch(false));