Avoid unneeded copy in BackendPlaySessionHandler plugin messages

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

@@ -146,7 +146,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
         .thenAcceptAsync(pme -> {
           if (pme.getResult().isAllowed() && !playerConnection.isClosed()) {
             PluginMessage copied = new PluginMessage(packet.getChannel(),
-                Unpooled.unreleasableBuffer(Unpooled.wrappedBuffer(copy)));
+                Unpooled.wrappedBuffer(copy));
             playerConnection.write(copied);
           }
         }, playerConnection.eventLoop())

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

@@ -225,12 +225,11 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
               backendConn.write(packet.retain());
             } else {
               byte[] copy = ByteBufUtil.getBytes(packet.content());
-              PluginMessageEvent event = new PluginMessageEvent(player, serverConn, id,
-                  ByteBufUtil.getBytes(packet.content()));
+              PluginMessageEvent event = new PluginMessageEvent(player, serverConn, id, copy);
               server.getEventManager().fire(event).thenAcceptAsync(pme -> {
                 if (pme.getResult().isAllowed()) {
                   PluginMessage message = new PluginMessage(packet.getChannel(),
-                      Unpooled.unreleasableBuffer(Unpooled.wrappedBuffer(copy)));
+                      Unpooled.wrappedBuffer(copy));
                   backendConn.write(message);
                 }
               }, backendConn.eventLoop())