Reproduce steps:
* Use Triple protocol in both consumer and provider,
* The provider works with `-Ddubbo.application.register-mode=instance`
* The consumer works with `-Ddubbo.application.service-discovery.migration=FORCE_APPLICATION`

Above test case will throw following errors:
```shell
[29/09/21 11:52:35:035 CST] NettyClientWorker-3-3  WARN channel.ChannelInitializer: Failed to initialize a channel. Closing: [id: 0xc1ba4a78]
java.lang.NullPointerException
	at org.apache.dubbo.registry.client.InstanceAddressURL.getScopeModel(InstanceAddressURL.java:498)
	at org.apache.dubbo.rpc.protocol.tri.TripleHttp2Protocol.configClientPipeline(TripleHttp2Protocol.java:76)
	at org.apache.dubbo.remoting.api.Connection$1.initChannel(Connection.java:115)
	at org.apache.dubbo.remoting.api.Connection$1.initChannel(Connection.java:102)
	at io.netty.channel.ChannelInitializer.initChannel(ChannelInitializer.java:129)
	at io.netty.channel.ChannelInitializer.handlerAdded(ChannelInitializer.java:112)
	at io.netty.channel.AbstractChannelHandlerContext.callHandlerAdded(AbstractChannelHandlerContext.java:938)
	at io.netty.channel.DefaultChannelPipeline.callHandlerAdded0(DefaultChannelPipeline.java:609)
	at io.netty.channel.DefaultChannelPipeline.access$100(DefaultChannelPipeline.java:46)
	at io.netty.channel.DefaultChannelPipeline$PendingHandlerAddedTask.execute(DefaultChannelPipeline.java:1463)
	at io.netty.channel.DefaultChannelPipeline.callHandlerAddedForAllHandlers(DefaultChannelPipeline.java:1115)
	at io.netty.channel.DefaultChannelPipeline.invokeHandlerAddedIfNeeded(DefaultChannelPipeline.java:650)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.register0(AbstractChannel.java:502)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.access$200(AbstractChannel.java:417)
	at io.netty.channel.AbstractChannel$AbstractUnsafe$1.run(AbstractChannel.java:474)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.lang.Thread.run(Thread.java:748)
```
.initialSettings(new Http2Settings()
                        .headerTableSize(config.getInt(H2_SETTINGS_HEADER_TABLE_SIZE_KEY, 4096))
                        .maxConcurrentStreams(config.getInt(H2_SETTINGS_MAX_CONCURRENT_STREAMS_KEY, Integer.MAX_VALUE))
                        .initialWindowSize(config.getInt(H2_SETTINGS_INITIAL_WINDOW_SIZE_KEY, 1 << 20))
                        .maxFrameSize(config.getInt(H2_SETTINGS_MAX_FRAME_SIZE_KEY, 2 << 14))
                        .maxHeaderListSize(config.getInt(H2_SETTINGS_MAX_HEADER_LIST_SIZE_KEY, 8192)))
                .frameLogger(SERVER_LOGGER)
                .build();
        final Http2MultiplexHandler handler = new Http2MultiplexHandler(new TripleServerInitializer(frameworkModel));
        pipeline.addLast(codec, new TripleServerConnectionHandler(), handler);
    }
    @Override
    public void configClientPipeline(URL url, ChannelPipeline pipeline, SslContext sslContext) {
        final Configuration config = ConfigurationUtils.getGlobalConfiguration(url.getScopeModel());
        final Http2FrameCodec codec = Http2FrameCodecBuilder.forClient()
                .gracefulShutdownTimeoutMillis(10000)
                .initialSettings(new Http2Settings()
                        .headerTableSize(config.getInt(H2_SETTINGS_HEADER_TABLE_SIZE_KEY, 4096))
                        .pushEnabled(config.getBoolean(H2_SETTINGS_ENABLE_PUSH_KEY, false))
                        .maxConcurrentStreams(config.getInt(H2_SETTINGS_MAX_CONCURRENT_STREAMS_KEY, Integer.MAX_VALUE))
                        .initialWindowSize(config.getInt(H2_SETTINGS_INITIAL_WINDOW_SIZE_KEY, 1 << 20))
                        .maxFrameSize(config.getInt(H2_SETTINGS_MAX_FRAME_SIZE_KEY, 2 << 14))
                        .maxHeaderListSize(config.getInt(H2_SETTINGS_MAX_HEADER_LIST_SIZE_KEY, 8192)))
                .frameLogger(CLIENT_LOGGER)
                .build();
        final Http2MultiplexHandler handler = new Http2MultiplexHandler(new TripleClientHandler(frameworkModel));
        pipeline.addLast(codec, handler, new TripleClientRequestHandler(frameworkModel));
    }
}