feat: replace CreateHTTPRequest with CreateHTTPRequestScriptVM

Allows the game client to make HTTP API calls from a listen server
(local lobby) instead of requiring a Steam dedicated server.
CreateHTTPRequestScriptVM has the exact same API signature but works
in both dedicated server and listen server contexts.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/vscripts/leaderboard_server.lua

@@ -39,7 +39,7 @@ function LeaderboardServer.prototype.setupEventListeners(self)
     )
 end
 function LeaderboardServer.prototype.loadLeaderboardFromServer(self, playerId, limit, offset, board)
-    local request = CreateHTTPRequest(
+    local request = CreateHTTPRequestScriptVM(
         "GET",
         (((((self.serverUrl .. "/leaderboard?limit=") .. tostring(limit)) .. "&offset=") .. tostring(offset)) .. "&board=") .. board
     )