rP19285 / D207 removed the only call to SendGetGameList.
The call was unneeded and a server shouldn't support unneeded getters that can cause performance issues.
The clients receive the gamelist on join and on update, so it's their duty of caching the data.
Therefore we can and shall remove the response and the C++ part.
(If the response would ever be used by a client that doesn't implement simple caching, then we should implement authorization serverside when reintroducing the removed lines.)