Don't fire a FML reset packet on first login, set it as required for the second join after the first.

Fixes #69

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/LoginSessionHandler.java

@@ -82,12 +82,6 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
             if (existingConnection == null) {
                 // Strap on the play session handler
                 connection.getPlayer().getConnection().setSessionHandler(new ClientPlaySessionHandler(server, connection.getPlayer()));
-
-                // This is for legacy Forge servers - during first connection the FML handshake will transition to complete regardless
-                // Thus, we need to ensure that a reset packet is ALWAYS sent on first switch.
-                //
-                // The call will handle if the player is not a Forge player appropriately.
-                connection.getPlayer().getConnection().setCanSendLegacyFMLResetPacket(true);
             } else {
                 // The previous server connection should become obsolete.
                 // Before we remove it, if the server we are departing is modded, we must always reset the client state.

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -164,9 +164,19 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     public void handleBackendJoinGame(JoinGame joinGame) {
         resetPingData(); // reset ping data;
         if (!spawned) {
-            // nothing special to do here
+            // Nothing special to do with regards to spawning the player
             spawned = true;
             player.getConnection().delayedWrite(joinGame);
+
+            // We have something special to do for legacy Forge servers - during first connection the FML handshake
+            // will transition to complete regardless. Thus, we need to ensure that a reset packet is ALWAYS sent on
+            // first switch.
+            //
+            // As we know that calling this branch only happens on first join, we set that if we are a Forge
+            // client that we must reset on the next switch.
+            //
+            // The call will handle if the player is not a Forge player appropriately.
+            player.getConnection().setCanSendLegacyFMLResetPacket(true);
         } else {
             // Ah, this is the meat and potatoes of the whole venture!
             //