Remove incomplete reconnect handler for certain session invalidations

This resolves #938 and #883

Note: This fix is not 'verified' in production (I waited over a week for
another full Discord outage and never encountered one), but I do have it
on record from b1nzy that Discord may send an OP9 with `{"d": true}`
during outages, so this would appear to be the proper fix.

The removed code seems to have been leftover from when ConnectionManager
was rewritten and never finished.

src/Discord.Net.WebSocket/DiscordSocketClient.cs

@@ -1,4 +1,4 @@
-#pragma warning disable CS0618
+#pragma warning disable CS0618
 using Discord.API;
 using Discord.API.Gateway;
 using Discord.Logging;
@@ -416,11 +416,8 @@ private async Task ProcessMessageAsync(GatewayOpCode opCode, int? seq, string ty
 
                             _sessionId = null;
                             _lastSeq = 0;
-                            bool retry = (bool)payload;
-                            if (retry)
-                                _connection.Reconnect(); //TODO: Untested
-                            else
-                                await ApiClient.SendIdentifyAsync(shardID: ShardId, totalShards: TotalShards).ConfigureAwait(false);
+
+                            await ApiClient.SendIdentifyAsync(shardID: ShardId, totalShards: TotalShards).ConfigureAwait(false);
                         }
                         break;
                     case GatewayOpCode.Reconnect: