[ISSUE-#7089] NacosRegistry register instance support PreservedMetadataKeys

[horizonzy]

What is the purpose of the change

For-#7089

[horizonzy]

@AlbumenJ PTAL

[codecov-io]

Codecov Report

Merging #7090 (079c18e) into master (4ad2634) will decrease coverage by 0.22%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master    #7090      +/-   ##
============================================
- Coverage     59.06%   58.83%   -0.23%     
+ Complexity      462      461       -1     
============================================
  Files          1043     1044       +1     
  Lines         42445    42473      +28     
  Branches       6222     6227       +5     
============================================
- Hits          25071    24991      -80     
- Misses        14574    14660      +86     
- Partials       2800     2822      +22     

Impacted Files	Coverage Δ	Complexity Δ
...org/apache/dubbo/registry/nacos/NacosRegistry.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...ng/transport/dispatcher/all/AllChannelHandler.java	62.06% <0.00%> (-27.59%)	0.00% <0.00%> (ø%)
...bo/config/event/listener/LoggingEventListener.java	37.50% <0.00%> (-25.00%)	0.00% <0.00%> (ø%)
...dubbo/common/status/support/LoadStatusChecker.java	46.15% <0.00%> (-15.39%)	0.00% <0.00%> (ø%)
...ng/transport/dispatcher/WrappedChannelHandler.java	47.82% <0.00%> (-15.22%)	0.00% <0.00%> (ø%)
...va/org/apache/dubbo/remoting/exchange/Request.java	74.50% <0.00%> (-13.73%)	0.00% <0.00%> (ø%)
.../remoting/transport/netty4/NettyServerHandler.java	56.81% <0.00%> (-13.64%)	0.00% <0.00%> (ø%)
...va/org/apache/dubbo/remoting/TimeoutException.java	22.22% <0.00%> (-11.12%)	0.00% <0.00%> (ø%)
...ava/org/apache/dubbo/config/DubboShutdownHook.java	63.82% <0.00%> (-10.64%)	0.00% <0.00%> (ø%)
.../remoting/transport/netty4/NettyClientHandler.java	57.62% <0.00%> (-10.17%)	0.00% <0.00%> (ø%)
... and 24 more

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[KeRan213539]

LGTM.
If the PR is merged, please update the corresponding document in https://github.com/apache/dubbo-website

[horizonzy]

LGTM.
If the PR is merged, please update the corresponding document in https://github.com/apache/dubbo-website

That's fine, also append a pr to use it in dubbo-sample.

[AlbumenJ]

LGTM.