Fix not forwarding channelReadComplete events in some cases

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/AutoReadHolderHandler.java

@@ -62,10 +62,14 @@ public class AutoReadHolderHandler extends ChannelDuplexHandler {
 
   @Override
   public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
-    if (this.queuedMessages.isEmpty()) {
+    if (ctx.channel().config().isAutoRead()) {
+      if (!this.queuedMessages.isEmpty()) {
+        this.drainQueuedMessages(ctx); // will also call fireChannelReadComplete()
+      } else {
         ctx.fireChannelReadComplete();
       }
     }
+  }
 
   @Override
   public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {