refactor ProtocolFilterWrapper$1 to FilterNode

[hengyunabc]

What is the purpose of the change

Currently, ProtocolFilterWrapper$1 often appears in the exception stack, and users will be confused. ProtocolFilterWrapper$1 needs to be extracted as a separate class.

[codecov-io]

Codecov Report

Merging #6962 (3e6b1c2) into master (3fc2d10) will decrease coverage by 0.04%.
The diff coverage is 59.52%.

@@             Coverage Diff              @@
##             master    #6962      +/-   ##
============================================
- Coverage     59.44%   59.39%   -0.05%     
+ Complexity      511      507       -4     
============================================
  Files          1028     1029       +1     
  Lines         41519    41523       +4     
  Branches       6037     6036       -1     
============================================
- Hits          24679    24661      -18     
- Misses        14104    14116      +12     
- Partials       2736     2746      +10     

Impacted Files	Coverage Δ	Complexity Δ
...java/org/apache/dubbo/rpc/protocol/FilterNode.java	57.50% <57.50%> (ø)	0.00 <0.00> (?)
...ache/dubbo/rpc/protocol/ProtocolFilterWrapper.java	81.81% <100.00%> (+18.02%)	0.00 <0.00> (ø)
...e/dubbo/remoting/transport/netty/NettyChannel.java	52.27% <0.00%> (-7.96%)	19.00% <0.00%> (-2.00%)
...ng/transport/dispatcher/all/AllChannelHandler.java	82.75% <0.00%> (-6.90%)	0.00% <0.00%> (ø%)
...mmon/serialize/kryo/utils/AbstractKryoFactory.java	75.43% <0.00%> (-3.51%)	0.00% <0.00%> (ø%)
...g/apache/dubbo/rpc/protocol/rest/RestProtocol.java	68.21% <0.00%> (-3.11%)	0.00% <0.00%> (ø%)
...g/apache/dubbo/config/AbstractInterfaceConfig.java	85.18% <0.00%> (-2.47%)	0.00% <0.00%> (ø%)
...he/dubbo/rpc/protocol/hessian/HessianProtocol.java	67.46% <0.00%> (-2.41%)	9.00% <0.00%> (ø%)
...n/java/org/apache/dubbo/config/RegistryConfig.java	84.12% <0.00%> (-2.39%)	0.00% <0.00%> (ø%)
...pache/dubbo/registry/support/AbstractRegistry.java	79.25% <0.00%> (-1.86%)	0.00% <0.00%> (ø%)
... and 9 more

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