Add experimental vanilla skin flow

Author: wode490390

src/main/java/org/itxtech/synapseapi/SynapsePlayer.java

@@ -151,6 +151,7 @@ public boolean isNeedLevelChangeLoadScreen() {
         return false;
     }
 
+    @Override
     public boolean isJavaClient() {
         return loginChainData != null
                 && loginChainData.getViaProxyAuthToken() != null

src/main/java/org/itxtech/synapseapi/multiprotocol/protocol11960/protocol/PlayerSkinPacket11960.java

@@ -18,8 +18,8 @@ public class PlayerSkinPacket11960 extends Packet11960 {
 
     public UUID uuid;
     public Skin skin;
-    public String newSkinName;
-    public String oldSkinName;
+    public String newSkinName = "";
+    public String oldSkinName = "";
 
     public boolean extend;
     public boolean error = false;

src/main/java/org/itxtech/synapseapi/multiprotocol/protocol11963/protocol/PlayerSkinPacket11963.java

@@ -15,8 +15,8 @@ public class PlayerSkinPacket11963 extends Packet11963 {
 
     public UUID uuid;
     public Skin skin;
-    public String newSkinName;
-    public String oldSkinName;
+    public String newSkinName = "";
+    public String oldSkinName = "";
 
     @Override
     public int pid() {

src/main/java/org/itxtech/synapseapi/utils/DataPacketEidReplacer.java

@@ -178,7 +178,7 @@ public static DataPacket replace(DataPacket pk, long from, long to) {
                                 cloned = true;
                                 dp.entries = dp.entries.clone();
                             }
-                            Entry entry = dp.entries[i].copy();
+                            Entry entry = dp.entries[i].clone();
                             entry.entityId = to;
                             dp.entries[i] = entry;
                         }