[pulsar-proxy] Fix memory leak with debug log-level

[rdhabalia]

Motivation

Right now, Proxy has memory leak debug log-level=2 because proxy parses RawMessage and doesn't release the payload. It can be easily and quickly reproducible by enabling proxyLogLevel=2 and publish messages across 10 topics.

#2:
	io.netty.buffer.AdvancedLeakAwareByteBuf.readByte(AdvancedLeakAwareByteBuf.java:400)
	org.apache.pulsar.common.util.protobuf.ByteBufCodedInputStream.readRawVarint64(ByteBufCodedInputStream.java:251)
	org.apache.pulsar.common.util.protobuf.ByteBufCodedInputStream.readUInt64(ByteBufCodedInputStream.java:218)
	org.apache.pulsar.common.api.proto.PulsarApi$MessageMetadata$Builder.mergeFrom(PulsarApi.java:4067)
	org.apache.pulsar.common.protocol.Commands.parseMessageMetadata(Commands.java:378)
	org.apache.pulsar.common.api.raw.MessageParser.parseMessage(MessageParser.java:65)
	org.apache.pulsar.proxy.server.ParserProxyHandler.channelRead(ParserProxyHandler.java:126)
	io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
	io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
	io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
	io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:323)
	io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:297)
	io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
	io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
	io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
	io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434)
	io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
	io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
	io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965)
	io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
	io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:648)
	io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:583)
	io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:500)
	io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:462)
	io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:897)
	io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	java.lang.Thread.run(Thread.java:745)

Modification

Release RawMessage payload to avoud memory leak.

[rdhabalia]

/pulsarbot run-failure-checks