[ISSUE #8712] Set namesrvAddrChoosed to null if choosed addr is not exist.

[qianye1001]

…ient is no longer in use, a new channel connection will be created.

Which Issue(s) This PR Fixes

Fixes #8712

Brief Description

How Did You Test This Change?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 47.41%. Comparing base (280804c) to head (71eb691).
Report is 31 commits behind head on develop.

Files with missing lines	Patch %	Lines
...e/rocketmq/remoting/netty/NettyRemotingClient.java	0.00%	4 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #8713      +/-   ##
=============================================
- Coverage      47.46%   47.41%   -0.06%     
+ Complexity     11543    11528      -15     
=============================================
  Files           1278     1279       +1     
  Lines          89524    89563      +39     
  Branches       11509    11516       +7     
=============================================
- Hits           42496    42464      -32     
- Misses         41805    41868      +63     
- Partials        5223     5231       +8     

Flag	Coverage Δ
	47.41% <0.00%> (?)

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[fuyou001]

CR need

[fuyou001]

LGTM