Revert "Fixes unused creation of REST clients for DiscordShardedClient shards. (#2109)"

This reverts commit 6039378c52.

src/Discord.Net.WebSocket/DiscordSocketClient.cs

@@ -152,8 +152,7 @@ namespace Discord.WebSocket
             LogGatewayIntentWarnings = config.LogGatewayIntentWarnings;
             HandlerTimeout = config.HandlerTimeout;
             State = new ClientState(0, 0);
-            if (shardedClient is null || parentClient is null)
-                Rest = new DiscordSocketRestClient(config, ApiClient);
+            Rest = new DiscordSocketRestClient(config, ApiClient);
             _heartbeatTimes = new ConcurrentQueue<long>();
             _gatewayIntents = config.GatewayIntents;
             _defaultStickers = ImmutableArray.Create<StickerPack<SocketSticker>>();