Username can be 16 * 3 bytes (#936)

see my pr #843

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLogin.java

@@ -143,7 +143,7 @@ public class ServerLogin implements MinecraftPacket {
   public int expectedMaxLength(ByteBuf buf, Direction direction, ProtocolVersion version) {
     // Accommodate the rare (but likely malicious) use of UTF-8 usernames, since it is technically
     // legal on the protocol level.
-    int base = 1 + (16 * 4);
+    int base = 1 + (16 * 3);
     // Adjustments for Key-authentication
     if (version.compareTo(ProtocolVersion.MINECRAFT_1_19) >= 0) {
       if (version.compareTo(ProtocolVersion.MINECRAFT_1_19_3) < 0) {